It wasn't really an open market since the US Gov was the only customer. They liked to spread money around to keep some kind of competition going. There were a lot of fans of the CM architecture. It did take substantial work to get a code running, but once you did the price performance scaling and stability was pretty nice. Enough people had gone through that process that there were plenty of codes that would have like to have continued running.

The generally accepted narrative is that TMC upper management really screwed up. More tactically the CM-5 really stumbled, with a host of hardware, system software, compiler and environment problems. Right before they folded it was starting to be a really nice platform to use. But very expensive, and the 2-3 years from the CM-2 to that point were quite dark.

If you look at the Cray machines from the last 5-10 years they are pretty similar to the CM-5 - fat tree-like guaranteed delivery message network with credits - commodity processors and the primary node type - attached vector processors - front end nodes running commodity OS

of course there are lots of subtle differences, but if you squint...of course the language environments aren't the same (except of course for parallel fortran :/)