LOS ANGELES — It seemed like a good deal. At first.

Last April, Netflix offered Kay Reindl and her longtime writing partner a substantial sum — in the mid-six figures, Ms. Reindl said — to oversee 10 episodes of a new sci-fi series, “Sentient.” It sounded like a lot of money for what they figured would be less than a year of work.

Ms. Reindl and her writing partner, who have worked steadily as TV writers since the 1990s, would be executive producers, instead of staff writers on someone else’s show. That would mean a lot more responsibility and much longer hours, but it seemed worth it. They found office space and hired a few writers.

Then came a surprise: they learned that “Sentient” would actually take 18 months from start to finish. When Ms. Reindl did the math, she realized that, under the new timetable, she would be making roughly the same weekly pay as the writers she was overseeing.

“It was a very bad day,” Ms. Reindl said.

Netflix declined to comment.

The rise of streaming has been a blessing and a curse for working writers like Ms. Reindl, who said she and her partner had ultimately left “Sentient” because of creative differences unrelated to the length of the series. On-demand digital video has ushered in the era of Peak TV, meaning there are more shows and more writing jobs than ever. But many of the jobs are not what they used to be in the days before streaming.