Well, the idea that Sony was always planning to bounce at some point isn't super surprising to me. The character was always on loan and there was never a given it would last forever. I hoped it would last longer than it did but, it was always a possibility one or both sides would walk.
The problem, is fandom convinced themselves that Spiderman belonged to Marvel/Disney and that Sony had no choice but to stick with the deal. From Sony's POV, After 5 MCU films, and an Oscar winning film and a hit Venom film, they think "we got this".
Yes, I know that makes fanboys mad when Spiderverse and Venom are brought up , but that's how Sony see's it. In their minds, they think a MCU-less Spiderman 3 and a Spiderman vs Venom film is money in the bank.
I think they've gotten a big head, and I think the road ahead is potentially more perilous then they realize, but alas , that's what they think.
But , as I've said before, studios, like people, learn from failure. Until the GA rejects their next offering in a big way , its full steam ahead, even if its toward an iceberg.