I can understand wanting to prioritize support for the cards people want to use most, but they should still plan to write software support for all the cards that have hardware support.
Imagine Nvidia not supporting CUDA on any of their cards. Unthinkable.
this is a-posteriori development.. we have no idea of how hard it is to implement with older GPUs
I've long since given up on my 5700xt getting supported. AMD is just not a good pick if you care about non graphics compute.