Comment by MountainTheme12

It's not just popularity, Epic has been trying really hard to solve it in Unreal Engine.

The issue is that, because of monolithic pipelines, you have to provide the exact state the shaders will be used in. There's a lot of that, and a large part of it depends on user authored content, which makes it really hard to figure out in advance.

It's a fundamental design mistake in D3D12/Vulkan that is slowly being corrected, but it will take some time (and even more for game engines to catch up).