We had a number of conversations about the fact that VS 2017 could be installed in any location, or multiple locations, and no longer created a registry key pointing to an install location. There's also the problem that an installation of VS 2017 may or may not contain C++ tools (as was the case with VS 2015.)
The solution proposed by the VS team-creating a tool called VSWhere-was inadequate for some scenarios such as Boost's because it would have required either caching a binary in your source enlistment or compiling code to locate the compiler. A number of people on this list asked for a more straightforward solution.
This doesn't fix the problem for all the versions of VS 2017 that are installed already. And this doesn't help our version numbers to make any more sense (although I'm pushing to fix that as well.) But at least in the future you'll be able to locate VS installs from a scripted environment.
Thanks for being loud and reaching out to us. As always, I'm happy to help you with any issues you might have with MSVC-just ask.