To make myself clearer, I don't particularly want anything to be canceled and - right now - I don't think there is any definitive reason to expect anything to be canceled, either. MS has never outright canceled an announced project before, and while that's not a guarantee they never will, fans wanting X-men really isn't a reason to do it now.
I just don't believe for a second that Armor Wars is any way safer as a project than any of the other movies currently announced. There may be a reason it was upgraded to a movie, but there's also a reason Rhodey is the very last og MCU character to get a project of his own despite him being the very first hero to appear in the MCU after Tony himself. And there's a reason his project was sent to D+ to begin with, and a reason it's not actually named after him, either.
And any theories about the movie being a sure hit because of the Iron Man connection just cannot be proven until we have actual evidence of audiences being willing to show up in equal measure for a replacement character, which we don't have yet. And they just don't make much sense in light of a project that doesn't seem that keen on using the Iron Man name, anyway.
You may be right it will be rebranded and Rhodey will become Iron Man, but that's 100% speculation at the moment and I honestly don't see anything they've done with Rhodey so far as at all likely to lead to him ever calling himself Iron Man. He's always been known to everyone as War Machine and he's been proud of it. Nobody ever asked him to carry Tony's legacy nor has anything ever even suggested Tony's legacy as Iron Man needs to be carried in any way. If anything, I expect Armor Wars to be about War Machine, Ironheart and maybe Rescue coming together out of respect for Tony to stop others from ruining Tony's legacy with knockoff Iron Man suits. Not about anyone becoming the new Iron Man.
All that aside, though, I think there is one very obvious point of analysis that can be made at this point:
If there really does come a point where the MCU needs to start canceling stuff, the first things on the chopping block will not be theatrical films of any title. It's the D+ series that are super-high budget and super-low return while also having far less audience satisfaction overall. At this point in time, despite some mixed reviews here and there, the MCU movies still only have a single actual flop in the post-pandemic era. The movies are doing fine. It's the D+ series that are taking tons of money and time and still not pulling their weight. The only possible way a movie gets canceled first is if Disney is so dug into 'making D+ a success' that they flat out refuse to allow Marvel to cut back on D+ content in any way. And I doubt that will really happen, considering Marvel has already cut back on D+ content by massively slowing down its D+ release schedule.
If Marvel needs to free up time and money, we're saying goodbye to Vision Quest, Nova, the Wakanda shows, Marvel Zombies, and future seasons of the shows that have already been made long before either Armor Wars or Eternals gets axed.