I actually find them to be extremely popular in C and C++, and also in some Lua communities.

They just have an extremely vocal opposition.

This is not too dissimilar to static builds and unity builds, which also "make your life easier" but people will write tirades about how dangerous they are.

I wonder if C++ modules (which I'm loving) will also get the same treatment, since they make a lot of clunky tooling obsolete.

I think SQLite's amalgamation is one of the reasons SQLite is so popular for embedding.

I like to combine the two and put a lot of single file libraries into one compilation unit. It compiles fast and puts lots of dependencies in one place that doesn't need to be recompiled often.