So I'll fall back on the "optionality" argument. Vendors, particularly small vendors, can experiment with RISC-V either free, or very cheaply more so than they can with ARM. Right there, RISC-V opens up a segment that didn't exist before. They'll be more experimentation. When your downsides are limited, but your upside is potentially huge, that's what I mean by "optionality". This is a powerful driver of success.

Naturally, any individual endeavour can fail, but collectively, there's going to be some huge winners.

My prediction is that RISC-V will open up some new category of computing. I can't tell you what it is, who will do it, or when they'll do it, because I don't know. My point is not so much that I can predict what it will be, but merely that there are forces in favour of RISC-V.

I am not, however, predicting the imminent demise of ARM.

I think also that a lot of commentators are viewing things through the lens of what we understand and the received wisdom today. Even - or maybe especially - experts tend to be hemmed in by what is "obvious".

RISC-V is like a genie that's been let out of the bottle. You can't put it back in.

By virtue of being open source, RISC-V won't vanish, no matter how many companies choose to adopt it as their ISA and fail.

Seems like, given enough time, one of those companies will just not die, and end up getting big.