They definitely aren't charging 10X for it, it's very much in line and competitive at the Xeon level in terms of pricing, and they shine for certain workloads, especially with the new interconnects (CAPI, NVLink). POWER8 was harder to find, but the performance characteristics were good (in my experiments). And now the software is better (more solid ports) and cost is down. I'm eagerly awaiting the chips to hit this year and trying to find access to some.
Plus IBM licenses the design these days (through OpenPOWER), so several of these players are building their own chips, boards, etc. Someone could inevitably enter the low-end market but lower-end devices have thinner margins and a lot more competitors.
Even right now you can get real chips to go on a board on pre-order, just under $400 (TALOS II preorders) -- the mobo is the pricier part, but part of that is likely due to the BOM choices on that piece from Raptor Engineering. A smaller form factor motherboard (maybe with 1 socket) could land in the sub $2000 range for a whole mobo+cpu -- which is certainly competitive with similar HEDT/workstation prices[1]...
[1] I just dropped $1,500 on a 1950X threadripper and associated mobo earlier this year, so this price range is certainly alive and kicking, IMHO.