Its misleading to call it "cost". In the C++ world only runtime cost matters. If using reflection allows to generate faster result code, it doesn't matter how long it takes to compile.
our company doesnt do compile on push on the server. It only does it when approved by a subset of ppl. The reason is we have a limited amount of servers and compile takes about 40min/variation. It's very annoying considering at prev job compile took about 10 min in total (project was organized better+ better servers) and there wasn't a limit at all-> compile at each push to gerrit.
I'm now trying to migrate from msbuild to cmake+sscache+PCH for std libraries while also trimming unnecessary includes to reduce suffering in the future - if not for me then at least for future developers. So I would say compile time is important for development. It causes other limitations too (like bugfixing becomes a huge commit with several squished fixes together to avoid recompiles, messing up git history or slower context switching when developing several features in parallel)
Even days of compilation may be an acceptable price for good optimization, as long as debug builds or builds with minimal optimizations are fast enough.
I'm now trying to migrate from msbuild to cmake+sscache+PCH for std libraries while also trimming unnecessary includes to reduce suffering in the future - if not for me then at least for future developers. So I would say compile time is important for development. It causes other limitations too (like bugfixing becomes a huge commit with several squished fixes together to avoid recompiles, messing up git history or slower context switching when developing several features in parallel)