That's why Stephen M Colbert was saying the more successful the more they'll do, the less success the less they will do...if each episode is about 25M then you might get another (full?) 6-episode season if it's really successful for this platform, if it's moderate or borderline successful and 30M/episode - 30M x 3 = 90M, you could get away with a 3-episode wrap of the series with only slightly higher budget to "Snyder Cut" and milk this section of the audience.
Plus all these Marvel shows are relying on the "MARVEL" brand except Loki where the lead's quite popular, but HBOMAX can draw on billion dollar franchise character/actors like Jason Momoa and Gal Gadot (400M US with one of the longest box office legs in superhero history) and even Ben Affleck for attention and subscriptions....I doubt Jeremy Renner, Anthony Mackay, Liz Olsen and Paul Bettany have the same star power.
and I don't know who has more diehard fans to subscribe, general audience are probably not that keen to just subscribe for Falcon and Wanda, but Disney+ still went for it.
As for season 2 if they do do get it it'd be say 2023, ZS is pretty quick at it. You probably have JLD and GLC as hit DC shows for 2022, then by 2021 they'd know if it's worth pumping out spin offs like BOP, Deathstroke, Cyborg etc from 2023/2024, I mean it's about milking it as much as you can lol.
IDK if the Affleck rumors are tru (prob not) but if he does agree for a streaming platform (with Ana as Catwoman lol), that'd be another power play say for 2025 then you could have ZS blockbusters from 2021 every 2 years and spin offs/2nd tiers like GLC, JLD, Cyborg etc in between....
It just depends on whether this thing tanks like 2017 TC JL or becomes a hit, in streaming matrix, then the floodgate will open, as was suppose to be the case in 2017