>The silence is deafening

Remember Amazon brought Annapurna Labs in 2015. And only released their first Graviton instances in 2018. The lead time for a Server CPU product is at least a year even when you have blueprints. That is ignoring fab capacity booking and many other things like testing. And without scale ( AWS is bigger than GCP and Azure combined ) it is hard to gain competitive advantage ( which often delays management decision making ).

I think you should see Azure and GCP ARM offering in late 2022. Marvel's exit statement on ARM server SoC pretty much all but confirmed Google and Microsoft are working on their own ARM offering.