Microsoft and Apple will probably switch to CHERI RISC-V for their Secure Enclave/TPMs once it has proven itself in the field. That means there will be hundreds of millions of CHERI RISC-V processors in the world.

Not to mention the smartcard market which would mean billions of processors around the world.

The Intel Management Engine famously runs MINIX. Tanenbaum has called it "the most widely used computer operating system in the world" - but it hasn't exactly led to mainstream MINIX adoption.

Smartcards often run Java Card, which solves the whole memory safety problem the other way around. You don't need CHERI for this kind of limited platforms: want to run memory-safe C today? Just ban all dynamic memory allocations. Throw in the usual UB restrictions and stick to a single thread and very little can go wrong.

What's important to remember is that, despite its large deployment figures, those are still niche applications. The number of people developing for them is a rounding error. There is no clear path from there to mainstream adoption.