I imagine after this we are going to strip back to more street, and world level threats instead of Galaxy and reality, and multiversal threats. We will get a new "main" MCU that will pull forward people that are still available, and still work.
They've already talked about the need to recast Tony Stark and Steve Rodgers, so this will almost certainly happen.
I have a mixed take on it...
On one hand, Iron Man is my favourite Marvel character and while RDJ did a great job with him, the MCU Iron Man diverged from the source material in a lot of ways. If a reboot/recast means that we get an Iron Man closer to the comics run (I'd love a late 80s/early 90s Iron Man/IMTAS vibe) then I'll be down, if only for some more Iron Man content that couldn't happen in the MCU as it currently exists.
I'd also be cautiously optimistic to see what they can do with the X-Men without leaning on the Fox continuity/actors.
On the flip side... even if this reboot goes as well as can reasonably be expected, they're gonna run into the same issue every comic publisher runs into when they hit the "reset" button.
Eventually the scope becomes too ludicrous and the continuity too inaccessible and every attempt to bring things back to basics works until it doesn't- because eventually the stakes will get ludicrous again and the continuity will become inaccessible again.
And as we've seen in comics themselves... hitting the "reset" button is a solution with diminishing returns.
Disney is big enough, with enough properties, they could do like Farmers and rotate the crops. Need to let Marvel rest for a decade after Endgame? Throw Gargoyle's up there (or something else)
Executives want to run the same thing that’s worked before endlessly until it doesn’t. That’s harmful and stupid.
Disney, if it was properly managed, could easily "rotate the crops." Problem is... they've ruined a lot of those seeds.
Live action remakes of their animated films were huge... until they ran those into the ground and now those returns have dried up.
Star Wars should be their ace in the hole any time they need a sure fire hit and create some distance for their other franchises, but that's been so mismanaged that even the genuinely good outings seem to be nothing more than rage bait for incel manchildren. They seem genuinely terrified of putting another Star Wars movie into theatres.
Indiana Jones is deceptive because it seems like it should be a huge thing but it's so tied to one actor who basically wants nothing to do with it anymore, and is too old to do anything else even if he wanted to.
They have loads of hot 90s animated properties that they could dust off but seemingly don't want to because they're not Marvel.
And finally you have the failure of stuff like Tron: Legacy, John Carter, and the Lone Ranger that convinced Disney to over-saturate with Marvel and Star Wars in the first place.
Who knows? Maybe Tron: Ares will be a sleeper hit, but I doubt it. Shame, because I liked Tron: Legacy and John Carter.
All in all Disney has a deep library where, if they were even a little bit savvy, they could rotate things so nothing ever felt stale... but they've handled their sure things so poorly lately that those aren't making any money... and neither will the smaller projects because of how ignored they've been.