The problem is, as usual, that some people want that support, but nobody is actually interested in helping out with that support - and that doesn't only include people willing to help out with the code, it includes things like CI. Just how the riscv targets won't be able to reach tier 1 without GH or someone else offering CI support.

Rust's target tiers, while historically not as enforced as they are today, have requirements attached to them that each target has to fulfill; demoting a target or removing support isn't done for fun, but because of what the reality reflects. In Windows 7's case, support from the Tier 1 Windows target was not so much removed as it was acknowledged that the support guaranteees just didn't exist - host tools had long been dead with LLVM having removed support for running on Windows 7, and tier 1 support wasn't guaranteed without any CI to test it on. Thus support was removed, and very soon contributors popped up to maintain the win7 target which is tier 3 and accurately reflects the support gurantees of that target.

(Not a jab at your situation btw, and I wish I could offer you a solution beyond the win7 target - but as it's essentially the preexisting Windows 7 support extracted into a target that matched its reality, it works quite well in practice)