Same would likely be true if they had evidence lots of customers used FreeBSD on their platform anyway. They wouldn't release architecture that couldn't run Linux, for example.
> they seem to have more than enough cash if they're making their own CPUs.
That's actually a cost saving exercise for AWS. The OpEx cost of a rack is a very large part of the cost of running cloud services. CapEx, staffing etc. makes up only a tiny fraction of it. The Graviton Arm chips are cheaper to run by quite a bit than Intel or AMD chips of comparable performance. Any expense spent in designing and producing their own chips is easily and quickly paid for by the OpEx savings.
I continue to hope that some day they'll invent some sort of "part-time contractor" position to provide me with ongoing funding for FreeBSD/EC2 work, but I certainly understand the argument that they should pay for EC2 specific work (like ENA) but not for FreeBSD development.
I might be wrong though (and a counter point is I assume Colin hosts Tarsnap/FreeBSD at AWS).