[Arizhel]

Taken as a whole, sure, but all those things you refer to in a browser are components, probably developed by different teams or even reused by entirely separate projects. By that measure, a modern Linux distribution is far more complicated than a web browser, since it includes a kernel, compilers, multiple web browsers, codecs, etc. The Firefox browser, for instance, I believe uses the SQLite database, so you can't claim that the Mozilla devs created that complexity, they just included it.

I think a compiler is different because you can't break it apart into separate projects like that. All the parts that go into a compiler are really only useful for that compiler, not as common pieces of "infrastructure" that can be used by many disparate larger projects.