After preliminary discussions with CPU vendors...
CPU vendors want to sell CPUs, while there are still plenty of running Sandy/Ivy bridge
expensive high-end machines running that would not be upgradable.
Not supporting machines that are 16 years old is ok, but restricting to < 6 years (7
years when Fedora 32 will be released) is crazy.
Requiring AVX would be more reasonable, as it will extend the maximum machine age to 9