I think I get your point: e.g. some part of your application absolutely needs the world's fastest NVMe as its local disk. Another part of your application just needs more cores from horizontal scaling. If you horiz scale to get more cores, you're also paying to put the world's fastest NVMe on each new machine.

Eh... I think you can achieve this in a simpler way with asymmetric scaling groups and smartly routing workloads to the right group. I feel like it's an ops/infra problem. There's no reason to constrain the underlying infra to be homogenous.