I was wondering the same thing and thinking about it.

When AMD bought ATI they viewed the GPU as a potential differentiator on CPUs. They've invested a lot of effort into CPU-GPU fusion with their APU products. That has the potential to start paying off in a big way sometime - especially if they figure our how to fuse high end GPU and CPU and just offer a GPGPU chip to everyone. I can see why AMD might put their bets here.

But the trade off was that Nvidia put a lot of effort in doing linear algebra quickly and easily on their GPUs and AMD doesn't have a response to that. Especially since they probably strategised on BLAS on an APU. But it turns out there were a lot of benefits to fast BLAS and Nvidia is making all the money from that.

In short, Nvidia solved a simpler problem that turned out to be really valuable, it would take AMD a long time to organise to do the same thing and it may be a misfit in their strategy. Hence ROCm sucks and I'm not part of the machine learning revolution. :(