Oh, you might be surprised how many people are not working on anything of consequence. Some of these companies don't even do much in the way of building stuff outside of the product teams, and even then, they frequently fizzle after some point.
You know the line "don't mistake motion for progress"? There's a whole lot of motion up in those SoMa offices... but very little progress. Some of these teams are very good at doing a lot of jiggling around while never accomplishing anything. They manage to snow their manager, which snows the next-level up, and if nobody calls BS, it just goes on like this.
R&D? When the response to building something new is an _immune system flare-up_ from the people who benefit from things remaining exactly as they are, there can be no R&D.
Just like the server situation, the employee situation is bloated beyond belief. You have people making messes and others cleaning it up, instead of just not making the mess in the first place (and then needing neither of those people).
If a million monkeys at a million typewriters would eventually produce the works of Shakespeare, some of these companies would likewise boil down to "three monkeys, ten minutes" (not my line but I love it).