I think Marvel know what they’re doing here, technically speaking there is no need for Spider-man to continue in the MCU, Far From Home basically gave the MCU the opportunity to say “Yeah, Spider-man? I mean he basically chose to just be a beat cop in super hero terms.” They don’t have to write him out, they don’t have to explain anything… they can basically just ignore him.
And they haven’t been horrible about it either, because while Sony wouldn’t be able to reference MCU stuff any more, they are also pretty set for just a local, New York based, super hero film.
What Disney have put to Sony here is whether Sony thinks they can make the same amount of money, even accounting for the 45% less cut that Marvel’s demands would have meant, without having the crutch of the MCU. I’m pretty sure that Sony were looking for a creative reboot and Marvel gave it to them. It wasn’t in Marvel’s interest to see Spider-man languishing in poor story-telling anyway.
I’m not as confident as some that they’ll work it out. I think Sony can and will perform a final movie that is completely independent of the MCU in an effort to get their spider-verse full fledged. If they have the creative talent now to do it without Marvel producing then they have got everything they needed out of the arrangement. And hey… Marvel kind of got what they needed too. I don’t think they’re going to sit around rueing the loss of Spider-man from the roster, they seem pretty happy with mining every depth possible, and it may well be the extraction of the rights for the Fantastic Four and X-Men that has had them take a “go big or go home” attitude to their arrangement with Sony.
Animosity towards Sony is understandable but I would want to wait and see what they decide to do if this is the new landscape. As I said above, there’s no reason to reboot Spider-man, not with the amount that they have invested in this alongside Marvel, and the success they’ve got from that. I think that if people end up having bad blood over a third Holland-fronted Spider-man movie simply because it isn’t in the MCU then I wonder what their love for the first two Spider-man films was anyway?
While there are obvious story ties to the MCU, to give some weight to a character without having to rehash the Uncle Ben storyline, both Spider-man movies have stood on their own two feet. Iron Man appearing, Happy and the Stark business being a backbone… these are just plot points that aren’t integral to the success that is Holland hitting a home run in how he’s playing Peter and a tonal shift in the telling of Spider-man stories that takes it away from previous failed trends.
tl;dr: MCU and Spider-man technically got everything wrapped up at the end of Far From Home, and both parties can reasonably walk away without canning the current Spider-man franchise. Edit: But TBH I’d still be surprised if they did, why close off financially successful avenues in either direction?