True, but a TPU v5p is supposedly much closer to an H100 than an A100 (the A100 and TPU v4 were fairly similar) — and you need the RAM as a baseline just to fit the model. I haven't seen super thorough benchmarking done between the two but the Google claims similar numbers. So, $/RAM/hr is all I can really look at without benchmarking sadly.
What matters is steps per $ and to some degree also speed (I'm happy to pay premium sometimes to get the fine tuning results faster).