I love how people say things like "extension spaghetti", as if all other non-standard APIs have the same problem: hardware gets new features that people want to use from that API, API gains extension to use that hardware feature.
CUDA is no different, in fact, often worse. Nvidia is bad at documenting which hardware does what things, and CUDA users often have to use third party tables to figure out what hardware can't do what and disappoint customers who unwisely invested into it.
The other platforms have better ways to deal with progress instead of "here find entries on dynamic libraries by yourself", and good luck.
Profiles and API versions are much better approaches.
It is no accident than the ongoing efforts to make Vulkan more friendly are moving away from extension spaghetti into profiles.