Earlier quoted context omitted.
You get considerably more ML FLOPS per dollar in a 4090 than any mac. It seems like the base M2 MAX is at roughly the same price point. It does grant you more RAM. Quadro and Tesla cards might be a different story. I would still like to see concrete FLOPS/$ numbers.
The M2 is a chip designed to be in a laptop (and it is quite powerful given its low power consumption). Presumedly they have a different chip or at least completely different configuration (RAM, network, etc.) in their data centers.
Even their high-end prosumer hardware could be interesting as an AI workstation given the VRAM available if the software support were better.