> When you consider ARM vs AMD vs Intel vs current-gen vs last-gen, AWS sells several 8-core 32-GB machines that have wildly varying performance characteristics.

This is actually a benefit of AWS and other large public clouds. You have a choice due to their size.

If AWS's investment in Gravitron design works well for your workload, it's a ~30% cost savings. They're able to invest in designing and producing the chips due to their size. A company like fly.to is limited in selection and heavy R&D.