If I remember correctly it's not just that AMD has poor support for their consumer cards, their Rocm code doesn't compile to a device agnostic intermediate, so you have to recompile for each chip. New and old Cuda compatible cards (like all Geforce cards) can run your already shipped Cuda code, as long as it doesn't use new and unsupported features. So even if AMD had supported more cards, the development and user experience would be much worse anyway where you have to find out if your specific card is supported.