The clock is ticking.

As early as Tuesday, television and movie writers could go on strike, creating the first major work stoppage in the entertainment industry in a decade.

The effects could be immediate. “Saturday Night Live,” which is having one of its most successful seasons in recent years, would go dark, leaving the show’s final three episodes in limbo. Late-night programs like Samantha Bee’s weekly “Full Frontal” on TBS and CBS’s “The Late Show With Stephen Colbert” would be forced to air repeats. The broadcast networks would also have to deal with the awkward affair at their annual upfront presentations in mid-May, with star-studded events aimed at attracting advertisers potentially marred by picket lines and protests.

But will any of this actually happen?

The Writers Guild of America and the Alliance of Motion Picture and Television Producers, which bargains on behalf of studios, have declined to comment on the state of negotiations while adhering to a news media blackout. But people briefed on the talks, speaking on the condition of anonymity to discuss private meetings, said that despite progress on some sticking points like health care benefits, a deal remained elusive and that negotiations would probably keep Hollywood in suspense until the final minute.

The guild’s contract expires at midnight Pacific time on Monday.

Among the writers’ other requests, they want studios to adjust the formulas that determine pay, especially for cable network and streaming-service shows. Studios are concerned about setting a precedent for talks with other unions, most notably SAG-Aftra, which represents actors and is to begin negotiating a new contract in two weeks. (The actors’ contract expires on June 30.)

But as tension rises — studios were expected to begin informing employees on Friday that a writers’ strike was possible — some senior writers, labor lawyers and longtime agents cited differences between the current environment and the circumstances of the last walkout as reason to hope a deal could be reached.

There are key distinctions between the talks taking place now and the 2007 discussions between producers and writers that led to a 100-day strike. Back then, there was a profound question on the table for writers: What was their place in a digital future?

The streaming era had yet to arrive — YouTube was only two years old — but writers wanted studios to carve out a robust compensation formula for programs distributed digitally. Studios, pointing to an uncertain future, wanted to limit payments. In particular, studios wanted to base residual fees for the reuse of programming online (say, reruns of old comedies) on a home video formula established in the early 1980s.

The proposal enraged writers. They had long resented the VHS and DVD residuals system, describing it almost from the moment they agreed to it as unfair. The writers’ unions saw the offer on digital programming as an attempt by studios to continue cheating them; most felt they had no choice but to take a stand.

As the talks grew increasingly acrimonious and a federal mediator was brought in, studios and networks developed elaborate contingency plans, including stockpiling scripts and ordering reality programming to serve as filler. For the most part, television networks were still operating from a position of strength; the decades-old television ecosystem — viewers tuning in at specific times and watching commercials; reruns delivering decent ratings — was more or less intact.

This time, negotiators are locking horns over more routine employment matters, including the shoring up of a faltering health care plan. The talks have been tense but not openly hostile. A federal mediator has not stepped in. And production companies have done almost nothing to prepare for a strike, which seems to signal that they may ultimately be prepared to offer a deal palatable to the writers.

The actress Katherine Heigl marches in support of the striking Writers Guild of America in 2007, the last time there was a work stoppage involving Hollywood writers.

Major media companies, while still generating enormous profits, are more vulnerable than they were in 2007. Most of the broadcast networks now attract only a small percentage of the viewers they did then. Cable networks are hurting as a result of cord-cutting by consumers. Two major movie studios, Paramount Pictures and Sony Pictures, are struggling because of a dearth of blockbusters. The DVD format is on life support.

Practically speaking, ABC, CBS, Fox and NBC would not be affected in prime time unless the strike bled into June. That is because production has mostly ended for the season, and writers have not yet begun to work on new series for the fall. A strike that lasted more than a month, however, could delay shows planned for the coming season.

Likewise, for cable networks and streaming services, shows that are scheduled to premiere over the next two months should be fine. But series that debut in the summer? Several of those are still shooting, and would probably be held up.

One wrinkle involves showrunners. In the past 10 years, as scripted TV has boomed — there were around 200 shows broadcast during the period of the last strike compared with over 450 released in 2016 — studios have aggressively courted big-name writers and showrunners like Shonda Rhimes and Ryan Murphy.

If major showrunners wanted to delay the premieres of shows in solidarity with writers, network executives dedicated to keeping them happy might be forced to listen — a prospect that would have seemed unthinkable a decade ago. If, say, David Benioff and D.B. Weiss wanted to delay the July premiere of “Game of Thrones” to show support for the writers, HBO executives could be in an awkward position. They have a business to run, but they also need to keep their star creators happy.

For now, networks are mostly concerned about a strike affecting their late-night shows. Though the ratings for such shows are down from where they stood years ago, the programs are experiencing a cultural currency they have not enjoyed in a long time. Hosts like Mr. Colbert, John Oliver of HBO’s “Last Week Tonight” and Trevor Noah of Comedy Central’s “The Daily Show” have become appointment television for disaffected liberals craving an antidote to President Trump.

The alarm at film companies has been mostly confined to marketing and publicity departments. The late-night sofa is an important promotional perch. What if the stars of May releases like “King Arthur: Legend of the Sword”and “Baywatch” were unable to drop by “The Tonight Show” to tout their latest wares with Jimmy Fallon?

The impact on movie production would be minimal. Most television series work on a just-in-time system of script delivery. Writers then commonly tweak jokes and dialogue as filming takes place. But most studio movies are assembled years in advance because the postproduction process — like digitally rendering entire cities — takes so long.

“None of the 2018 movies will be affected,” Kevin Feige, president of Marvel Studios, told reporters in mid-April, referring to films like “Black Panther” and “Avengers: Infinity War.” “Most of them are set. What it would really impact is future work on future projects.”

A strike of more than a couple months could, however, hurt future movies, particularly those with Oscar aspirations, as studios move forward with production on scripts that are not quite up to snuff. During the last strike, several films required last-minute script doctoring but studios were out of luck.

The James Bond movie “Quantum of Solace” was one. Daniel Craig, who played 007, later said of the predicament, “There was me trying to rewrite scenes — and a writer I’m not.” Similarly, the director Michael Bay blamed the poor critical reception of his “Transformers 2: Revenge of the Fallen” on the 2007 walkout.

“It was very hard to put it together that quickly after the writers’ strike,” Mr. Bay told Empire magazine in 2011. “It was just terrible to do a movie where you’ve got to have a story in three weeks.”