Maybe in 5-10 years, RISC-V gains share in initial designs, but the semiconductor design process is loooong.
And if you're going to talk about Microcontrollers and simpler chips, keep in mind we had a bunch of other RISC architectures a decade ago that all lost to Cortex-M for simplicity/cost reasons (RIP MIPS).
But all that will be left in a few years is the high end areas and where there is a lot of lock in to the ISA.
It isn't yet clear when RISC-V will be ready to compete at the highest end of things, but that is where Jim Keller comes in.
RISC-V is a classic market disruptor for ARM, just as ARM was a disruptor to Intel.
So RISC-V really only needs to focus on CPU cores to be an existential threat to ARM.
At this point their biggest most is probably the patents on AMBA specs, but if they tried hard to enforce those the industry would switch to something like TileLink in a relative heartbeat.
Integrators don't typically go all in on ARM IP though for a couple major reasons. 1) They want to provide some value add beyond the standard offerings or else why pick them over a competitor? 3) They have massive collections of IP blocks already that they don't have pay ARM for. Maybe it takes some engineering to convert to the next chip, but that's probably cheaper than what ARM is asking for.