As far as I can tell, what happens at these companies is that they started by concentrating almost totally on product growth. That’s completely and totally reasonable, because companies are worth approximately zero when they’re founded; they don’t bother with things that protect them from losses, like good ops practices or actually having security, because there’s nothing to lose.
The result is a culture where people are hyper-focused on growth and ignore risk. That culture tends to stick even after company has grown to be worth well over a billion dollars, and the companies have something to lose. Anyone who comes into one of these companies from Google, Amazon, or another place with solid ops practices is shocked. Often, they try to fix things, and then leave when they can’t make a dent.