It only runs, what, 90% of PCs, laptops, and servers in the world?
PCs are like 5% of computing devices. Very important for business offices but not outside of that niche. And mass amounts of servers can be adapted to whatever is cheapest. Google wouldn't insist on AMD64 - they'd port to ARM if ARM was cheaper. And if you do want AMD64, AMD currently makes better AMD64 chips.
Nah they've been "out of fashion" for 5+ years, and in that time AMD took their datacenter crown, which was also encroached on by various ARM hyperscaler systems.
Maybe a decade ago, but they have lost market share every year since and currently sits around 60% and it still decreasing.