[corysama]

In gamedev it takes 7-10 years before you can require a new tech without getting a major backlash. AMD came out with AVX2 support in 2015. And, the (vocal minority) petitions to get AVX2 requirements removed from major games and VR systems are only now starting to quiet down.

So, in order to make use of users new fancy hardware without abandoning other users old and busted hardware, you have to support multiple back-ends. Same as it ever was.

Actually, a lot easier than it ever was today. Doom 3 famously required Carmack to reimplement the rendering 6 times to get the same results out of 6 different styles of GPUs that were popular at the time.

ARB Basic Fallback (R100) Multi-pass Minimal effects, no specular.

NV10 GeForce 2 / 4 MX, 5 Passes, Used Register Combiners.

NV20 GeForce 3 / 4 Ti, 2–3 Passes, Vertex programs + Combiners.

R200 Radeon 8500–9200, 1 Pass, Used ATI_fragment_shader.

NV30 GeForce FX Series, 1 Pass, Precision optimizations (FP16).

ARB2 Radeon 9500+ / GF 6+, 1 Pass, Standard high-end GLSL-like assembly.

https://community.khronos.org/t/doom-3/37313