"RISC-V-based" does not automatically mean "open". Vendors who put RISC-V in an SoC are free to add their own PSP or ME equivalents. Also, the processor itself is a small portion of a fully functioning computer. Things like GPU, wifi, bluetooth etc are most likely going to be proprietary.

Do you know of a RISC-V CPU suitable for desktop use? As far as I know, no one yet produced any silicon for that market.

Seriously, I don't know of any publicly available RISC-V silicon with even an MMU, say nothing of 'desktop' class.

SiFive announced that at Hot Chips 2017 (last week): their quad+1 core is coming out early next year.

In addition to that, I expect to see some interesting announcements at the RISC-V workshop in Nov.

Patience, patience. It's likely that RISC-V adoption will happen bottom up, first deeply embedded space (like NVIDIA, who is using it internally in the GPU for managements). Next, bigger cores will also happen especially where there's no (perceived) advantage to using ARM. A standalone chip will probably come late and will likely come from China from someone looking for a way to stand out from the myriad of ARM vendors out there.

Just the idle musings of an ARM-chair analyst.

You say 'also' but aren't elaborating sufficiently.

It's too bad modern high-performance consumer CPUs are all paired with non-free platform services (Intel ME, AMD PSP) that provide attack vectors for organized crime and governments.

Nobody cares about ME/PSP/etc. You might, but nobody will stop buying these chips just because of that.

I care, and I'm not alone. The problem and it's consequences aren't widely known outside of the tech community.