Pretty bad take given that Android recently transitioned from 32 bit ARM to 64 bit ARM, which are essentially totally different ISAs and 64 bit ARM was used in

Pretty bad take given that Android recently transitioned from 32 bit ARM to 64 bit ARM, which are essentially totally different ISAs and 64 bit ARM was used in absolutely nothing at all before Phones -- iPhone 5s first, then Android a couple of years later with e.g. Galaxy S6. The one advantage that transition had was that the same CPU could run both ISAs -- something ARM has dropped in their latest (and all future) 64 bit-only CPU cores. And for some time now apps could still be 32 bit but the OS had to be 64 bit. A transition to RISC-V will be cold turkey. It's technically possible of course to build one CPU that can run both A64 and RV64, but only ARM can legally do it, and they probably won't unless they're really losing, sometime 5 or 10 years from now.