You have talked about everything but what the parent was mentioning- actual cache. As in, L1 and L2. Those vary sizably among the different price tiers, somewhat understably, for reasons related to this.

On recent IBM Power chips, there's a so called PowerCore option that turns off half the cores, and lets the remaining cores double their L2. On some workloads that's a net win. I also tend to think it's there for those people paying a pricey per-core or per-socket fee, where a modest 15% performance gain/core could be very rewarding in a way that scale-out/more-cores can't replicate, but that's in a different realm than anyone I know.