> If you're looking for fundamental material, the last thing you want is learning a very (not slightly) outdated and weird API.

I've never seen a more detailed tutorial than LearnOpenGL that actually goes through the concepts of graphics programming thoroughly and actually make things other than just "learn how to use the API". That alone should be enough to cement the site's longevity.

> And OpneGL is worse

It's never late to learn Vulkan / DX12 after learning learnopengl.com! The value of learnopengl.com isn't in the APIs, it's about learning the basic concepts of graphics programming. If you start learning with Vulkan without any prerequisite knowledge, you'll be bogged in low-level details from the start that isn't really related with learning the actual fundamentals. (And you'll probably have to unlearn Vulkan and DX12 again once a new API has surfaced)