Well we also have the point that Marvel has not generally recast roles when actors leave.
Notable exceptions like Hulk, where the first film wasn’t successful. And whatever the hell went down with Terrance Howard.
We got a new Captain America, not a new actor for Steve Rogers. We’re getting a different Iron Man related character, not a new Tony Stark. They didn’t recast black Widow. They introduced Yelena.
There are clear “on deck” characters to transition to for others (thinking of Hawkguy, and now Hulkand Thor).
There was a lot of speculation and discussion about how Marvel would handle actors like Chris Evans hitting the end of their contracts and moving on. Or what would go down if anyone eventually aged out.
They’re pretty clearly, and explicitly not recasting Bond style. They’re handing off titles, or putting related and equivalent characters in those spots.
So a recast here. Again may have been the better move creatively, and given the special circumstances. But it doesn’t fit with their overall approach to the MCU.