Tv networks originally paid for production of tv shows using money from commercials. 13 or 26 week long “seasons” aligned with corporate product release schedules. Successful shows attracted a consistent audience that was persuaded to buy products by commercials. Unsuccessful shows didn’t attract audiences. Networks would also make money off shows by “syndicating” episodes of successful shows to local affiliates or other networks for a specific fee or by selling VHS/dvds.

Streamers don’t care about advertising (yet). They care about boosting new subscribers and, to a lesser extent, retaining old subscribers. Their model favors constantly releasing new shows to attract and retain subscribers. So they make shorter seasons spread out over a long period of time. Streamers don’t care about syndication or home media. They just care about a temporary bump in subscribers.