I am not sure if cloud providers want ARM - the most valuable resource is rack space, so you want to use the most powerful CPU, not the one using less energy.
The limit is power capacity and quite often thermal. Newer DCs might be designed with larger thermal envelopes, however rack space is nearly meaningless once you exhaust thermal capacity of the rack/isle.
Performance within thermal envelope is a very important consideration in datacenters. If a new server offers double performance at double power it is a viable upgrade path only for DCs that have that power reserve in the first place.
Well, Amazon does offer Graviton 4 (quite fast and useful stuff) along side their Epyc machines so there is some utility to them. A 9654 is much faster than a Graviton 4.
Cooling takes up rack space, too. There also are workloads that aren’t CPU constrained, but GPU or I/O constrained. On such systems, it’s better to spend your heat budget on other things than CPUs.
The limit is power capacity and quite often thermal. Newer DCs might be designed with larger thermal envelopes, however rack space is nearly meaningless once you exhaust thermal capacity of the rack/isle.
Performance within thermal envelope is a very important consideration in datacenters. If a new server offers double performance at double power it is a viable upgrade path only for DCs that have that power reserve in the first place.