I doubt library writers will care beyond anyone involved in the project. That said, it's possible to port CUDA code already with a bit of work, so not quite from scratch in any case:
Contrary to what buzzword happy SV types would have you believe, most "real" HPC work isn't machine learning (r/gatekeeping, I know). Particle physics, computational fluid dynamics, network simulations, etc. Lots of it is already written in CUDA. HIP, using hipify, can translate the already written CUDA code to HIP, which is GPU-agnostic.
2. The parent comment was about translating existing code written in CUDA to be used on an AMD GPU, not about developing new software- if it were about developing new software, they'd be starting from scratch with 01.org tools, which is what everyone wants to avoid. 01.org doesn't have any translation tools for this.