Costs (salaries) can balloon on successful series. It's also the case that, if a series is getting close to the number of episodes that can make for profitable syndication deals, it made sense (in the context of network TV) to stretch things to that point. It's also the case that, as long a series is still doing pretty well, odds are that putting something new in its slot will be a net negative.
Traditional broadcast also just had different incentives than streaming.
A successful sitcom captured a lot of eyeballs that could be translated into advertising dollars. It could also be a magnet for viewers to watch perhaps somewhat less captivating content in adjacent timeslots a la "must see TV Thursdays on NBC."
Netflix, on the other hand, mostly needs to fill its catalog and have enough really must see content so that subscribers keep renewing.
There's overlap between the two models. Both reward series that people really want to watch. But the specifics are subtly different.
Traditional broadcast also just had different incentives than streaming.
A successful sitcom captured a lot of eyeballs that could be translated into advertising dollars. It could also be a magnet for viewers to watch perhaps somewhat less captivating content in adjacent timeslots a la "must see TV Thursdays on NBC."
Netflix, on the other hand, mostly needs to fill its catalog and have enough really must see content so that subscribers keep renewing.
There's overlap between the two models. Both reward series that people really want to watch. But the specifics are subtly different.