They want to become like ARM? I don't want to sound ominous, but I personally don't think it's ever going to happen.
I'm not going to go into all the details of why I don't, but one first major point is that RISC-V is nothing like ARM. It's an open-source ISA, and it's the main reason why it has gotten that much traction, especially in asian countries. It's a key to independence for everyone using it. ARM both owns the ISA and the cores. That's a very different business model. ARM has already had its own set of difficulties, but say they opened-sourced their ISAs and I don't give them much time before the beginning of the end for them.
Yes, many are jumping on the RISC-V bandwagon, and many are doing that on their own rather than call SiFive. That's not something you could ever do with ARM.
Even if SiFive was very, utterly, extremely good with their cores, customizations and customer support, that probably would never be enough to get to the point where ARM has gotten (and may fall from one of these days, probably the days are counted.)
More generally speaking regarding startups in general, the business models of startups are almost never sustainable. That's not what a startup is. And startups also almost never become big, established businesses - they eventually get sold to a big fish, or die. That's what the destiny of a startup is. And in this particular case, while I don't have all figures about SiFive's results and how healthy they are, I wouldn't be surprised if they were not *that* healthy.
Let's just recall that they "almost" got sold to Intel. Even if one can consider the failure a good thing here, whatever really happened, a failed acquisition for a startup is never a good event financially speaking.
Just a few thoughts. I've known quite a few startups and have worked in a couple, and all this looks unfortunately pretty familiar.
So anyway, good luck to them. Unless, of course, they get some "unexpected" help from the US, desperate to fight China, who knows. And curious again to see what's going to happen in the coming months/years.
Also just curious to have some insider views.