All well-behaving software will of course check if AVX is supported before trying to use it, but at least in some cases that just means they'll refuse to instal

All well-behaving software will of course check if AVX is supported before trying to use it, but at least in some cases that just means they'll refuse to install or run on systems that don't have it: https://www.pro-tools-expert.com/production-expert-1/2019/9/5/is-this-software-issue-the-final-curtain-call-for-old-mac-pro-cheese-graters-used-in-todays-recording-studios https://www.pro-tools-expert.com/production-expert-1/2019/9/... (Developing parallel code paths and keeping them working indefinitely is a lot of extra work, and AVX has been around for close to a decade at this point.)