Thing is, though, I think it's fairly safe to say that the main compiler "vendors" are Microsoft, GCC, and Apple to some extent. The vast majority of software is produced either using Visual Studio, gcc, or Apple's version of gcc, or clang.
Visual Studio is (sadly) the gold standard on Windows. It may not be free, but companies (including startups) will pay for it if they need it. GCC is of course free, as is clang. You'd be foolish to pay for a toolchain unless you have very specific needs. So what other compiler vendors that make money off their toolchains are actually relevant for all but niche uses? I'd guess that their aren't any, but I can't claim to have comprehensive knowledge of everyone's toolchain needs.
