[royjacobs]

Not everyone wants to use existing engines. Or are you saying you want to embrace vendor lock-in in that regard?

[pjmlp]

Yes, definitly, that is the approach taken by AAA game studios.

A plugin framework for 3D APIs is probably the easiest part to implement on a game engine, specially when API like OpenGL and Vulkan already require implementing one due to extension spaghetti.