In the TV business, seasons are the time period where new and returning shows debut, usually running from September to May each year. NBC, CBS, ABC, Fox, and The CW all put their best stuff on in the Fall, and debut a few extra shows later on mid-season. That's how they always operated, and that's how they will continue to operate till the end of time.

By contrast however, cable and streaming networks have always just debuted seasons and shows whenever they felt like it. They don't stock pile most of their premieres for the Fall, instead spreading them out over the course of the September - May period, some even premiering in the summer. So why aren't these types of networks beholden to the traditional TV season rules?

Is it simply because cable traditionally broke the mold decades ago and they don't have or need to be?

Things have changed on the broadcast networks: in the first Golden Age, seasons often ran 39 episodes. Now it's common for shows to only have 22 or even 16-episode seasons.

The streaming companies rely on subscribers to keep the service going, and don't rely on advertising revenue. Therefore, there's no good reason for them to worry about following a traditional television season, and plenty of reason not to: who would keep paying for a service over the summer which ran only reruns during that period?