>> Does it mean that I can’t compile with -mavx2 anymore?

> You already can't if you're shipping binaries to users unless you only support Skylake & newer?

Huh? My 6+ years old gaming PC supports AVX2, and it definitely doesn't have a "Skylake & newer" CPU!

AVX2 support started at Haswell, or Intel core 3rd generation. We're at gen 10 now.

While there certainly are still a lot of systems without AVX2 support, new games (and other performance hungry software) requiring it would not be completely unreasonable.