These are just my guesses but: Software for TPU is still in its early stages. CUDA is well established. You can test on a gaming GPU that you can find (locally

These are just my guesses but: Software for TPU is still in its early stages. CUDA is well established. You can test on a gaming GPU that you can find (locally!) in many markets. XLA is meant to solve this, but first impressions matter and my first impression was that it has not yet "solved" this issue. TPU is only available via Google Cloud - as far as I know they don't have NVIDIA's widespread distribution to various HPC/supercomputer systems. This also has implications on scaling up more than a few pods, as they will need to be colocated with speedy interconnect (which is provided by the various existing HPC systems that use NVIDIA's chips). Finally, I think many people are discovering that the supposed benefits of TPU are marginal at best in the face of the types of natural scaling issues that both GPU's and TPU's suffer from when scaling out to e.g. hundreds of pods. I'm certain that someone with more experience than I could give a better answer though - and again, all speculation. I refuse to use TPU because Google Cloud's system for getting access to said TPU's was horrible for me when I tried it. I believe John Carmack has a nice tweet thread specifying the same issues I ran into. In general, Google has a habit of developing tech for other Googlers first, and as such winds up ignoring a lot of real-world scenarios faced by researchers/practitioners. NVIDIA on the other hand has been working directly with a ton of institutions and businesses ever since the inception of CUDA. That their TPU's have seen any adoption at all is mostly due to their research program which granted very cheap access to TPU's to tons of people.