I scarcely go a week without encountering issues caused by their huge CMake 4 backward compatibility break. I think CMake has one of the worst solutions out there.
Hasn't been an issue at all for me, but in any case that's a separate issue. They removed compatibility with CMake earlier than 3.5, which is 10 years old at this point. Support length is orthogonal to default behaviour evolution systems.
I never encounter things which need CMake <3.5 features. I constantly encounter things which declare their "minimum supported version" to be below 3.5.
Which makes a lot of sense for those projects! They can be built with CMake 3.2 because they don't need anything introduced in a newer version, so why not declare 3.2 to be the earliest supported version? It's not their fault that CMake interprets "minimum supported version" weirdly?