[Followerer]

This is corporate mindset 101. Questions like "why don't you do X" make no sense to a corporation. The question is always "why should I do X". Every decision has a cost and a benefit, and things happen when benefits outweight the costs proportionally to the implicit risk.

Companies have been successfully working with ARM for a loooong time. It's a massive, well supported, ecosystem that works quite well (no customer complains about delayed/cancelled products related to ARM's performance). What does RISC-V offer that's worth jumping into the void?

That's startup territory, you won't see big companies betting big on RISC-V for a while, if ever.