The first Avatar was 1 million per episode but most of that was either spent on plane trips to China or on Mako's/Mark Hamill's/Tress MacNeille's pay check and cost more to make then other cartoons of it's day.
Korra on the other hand was only $200,000 to $300,000 per episode for the Mir episodes of books 1 to 3, the later because Mir wanted more money, book 4 however was only $90,000 a episode, Korra's budget cheap enough to improve everything else not only to Korra but enough to get near feature quality animation back as was the case in the 80s & 90s.
Pierrot's episodes however were $800,000 a episode due to Japanese animators get paid more then Korean animators but since Mir did a better job and was cheaper Pierrot was fired and Mir was bought back.
Voltron:LD is only $90,000 a episode and is the only cartoon streaming new of days that is even trying, as well as the fact that everything else is $10,000 a episode at best, some times $20,000-40,000 if the show is ditched over seas to places like Korea, Taiwan, The Philippines and China but seeing what VLD is doing with only $90,000 a episode, $500,000 will bring near back feature quality animation done by AAA Japanese studios again, just like in the 80s & 90s.
At a million a episode it should not only stay in the States but it should mostly be animated on 1s (24FPS) as well, matching that to Tex Avery & Bob Clampett.
None of those shows were trying to ape Avatar due to being flat & lifeless.
Granted, Green Lanturn was CG and Young Justice did have some construction, but they lacked the effort that Avatar had and Avatar was still amateur hour and American networks don't use sponsors anymore (99% of the time), American networks use their own money from their own wallets to fund the shows themselves, this is not Japan.