> TBH the "ZIRP overhiring" seems like the most likely real reason. I could never understand how all these companies could hire so many people for so much money, only to have them work on later-to-be-cannes open source projects.

The same way they hire so many people for so much money to work on AI projects and build datacenter which haven't produced actual revenue for any customers (corporate or otherwise). I'd rather light money on fire to employ people tbh.

I say this as someone who has the 200 dollar Claude sub.