Is RISC-V the be-all, end-all? No, but it could help them get a lot closer than they're likely to get with any of the proprietary ISAs.
This is just like Debian generally does not write new useful software to put into Debian, and instead depend on outside, “upstream” authors to write software. Some other organizations, like FSF and its GNU project, will have advocacy roles, and do have the incentives to write new software and to help porting to new architectures. It is there that the motivations for this work must be found. Of course, individual people can be involved in more than one organization, and many Debian people happen to be enthusiastic advocates, and will in fact often do this work. But the reason for them doing this work is not, mostly, rooted in them being a part of Debian.
Therefore, and this is my point, if you want this work to be done, you can’t exhort Debian to do it. It will not work. Ask instead why someone else, whom you think should be motivated to do the work, does not do it.
If they conflict with RISC-V's own space, the chip can't use RISC-V trademarks.
And, of course, the RISC-V Consortium will never adopt proprietary extensions, as that goes against its core values.
