I'm also just a normal tech person, so my answers may be inaccurate.

My understanding is:

1. ARM seems superior in the mobile computing domain where efficiency matters more than raw power. I wonder if that's related to the RISC vs CISC instructions... if that's the case, having an open architecture alternative to ARM would allow any manufacturer to create their CPU designs without having to pay a hefty fee to ARM. Should bring more competition and won't keep manufacturers hostage of ARM. If ARMs raises their royalties 1000x, Apple, Qualcomm etc just have to comply for lack of alternatives, and consumers end up paying the price. This won't be possible with RISC-V
2. I can definitely see this happening, or at least having the option. OSs and apps will have to build for that new architecture of course, which takes time and money. I'm personally particularly excited about laptops
3. I guess. I don't think it's ever impossible to do this, it's always a matter of how much of an impact it has on performances

If I said something stupid, please let me know, I'd like to learn about this!