As far as cloud service servers are concerned, I don't think ARM CPUs have any meaningful marketshare, right?
You could start running things on ARM, but, almost certainly, that comes with a lot of extra friction. (Not saying that isn't a bad idea, it'd probably improve the ecosystem as a whole and flush out architecture-specific assumptions in server software. But it's not someting trivial to do.)
AWS graviton, Google Axion? ARM has better performance per watt, which translates to better performance per $.
Linux on Arm works great. I barely notice the difference except everything is a bit faster. Most SaaS companies can and should switch.
AWS Graviton has been steadily gaining share, a quick Google search says it's up to 20% now.
Arm has been growing fast for years, recent stories claim ARM is at 50% for hyperscalers (google, amazon and microsoft are making their own designs) and 25% for general servers according to stories from this year, and the share is growing fast.
x86/64 is looking more and more like the next Alpha or MIPS in many ways.
Surely having AWS Graviton in service for nearly a decade will mean it's not that much friction.
More than 50 % of new CPU capacity on AWS is arm. Most of their own stuff uses it, nitro co processors are also arm. Anyone caring about cost of AWS has or is transitioning.
AWS runs a lot of ARM server and they are pushed heavily since they are cheaper and faster. And with Apple running ARM it is just easier to fully transition now.