Are they killing their products due to lack of demand (which seems odd, given the cost/benefit), too much competition from Amazon, running out of money vs. ramping up sales, or??

I just googled and it looks like the Ampere Altra is shipping in some rackmount configs? (Vaporware?)

https://www.gigabyte.com/Enterprise/Rack-Server?fid=2326,222...

https://www.avantek.co.uk/ such as https://store.avantek.co.uk/ampere-altra-mt-jade.html

https://amperecomputing.com/reference-platforms/