Very few, entreprise users (aka volume) will pay the license, hobbyists will pirate it if need be.
AMD doesn't want to do support for the hobbyists for free, that's all.
I mean, over the years, I have purchased (or advised other people to purchase) multiple Nvidia GPUs for compute workloads.
And the reason pretty much always came down to good integration between various open source software and proprietary CUDA drivers. And the assumption is that this support will continue for many years.
So, yeah, burning their existing FPGA users is a strong signal never to invest real money in their GPUs for compute workloads.