I do not miss Google's monorepo one iota. It had huge benefits, but after stepping back far enough the result also easily begins to look a little like Stockholm syndrome. Anything they want to open source they basically have to rewrite from scratch because of that godawful repo, never mind reasoning about what actually ended up in your binary on any particular day when depending on such a gargantuan tree, and of course not to mention what by now is likely 10s of FTEs dedicated simply to managing the tree.

Those millions of LOC mostly only existed to serve their own purpose, and possibly the intrigue of many a doe-eyed eng. If I came across a codebase like that today, I'd likely be quite vocal on reallocating the evidently outsized engineering budget to some more productive use