Because I previously worked on the Chromium codebase at Google I have a 'specialist' dev workstation, an HP Z840 dual 18 core Xeon with 256GB of RAM. And that's a model from many years ago now, the newer specialist workstations are even heftier. To work on chrome @ Google you absolutely need one.
That said, if you're using cached builds via goma and have a nice fat pipe it can go quite fast without making your machine sweat much.
It's an absolutely massive code base. I wish I could explain why, but it is. No single part sticks out as bloat to me. I could never get CLion (among other tools) to index it properly.