Ah, but they'd make less money that way. That's why they spread it out, so you stay subscribed.One thing I'd prefer these days is that if the entire season is done being made... then it should just be released ENTIRELY for streaming purposes so you can watch all or most of it in one go.
Though in the case of the Live Action shows, they're usually not finished when they start airing.
I think Picard Season 3 might be the first exception, the showrunner said it's been complete since September.
Not sure if the animated shows are completely finished when they start airing, but probably.