Google care so little about design they've just spent the last few years trying to get everyone to use their Material guidelines, and Google's doodles are legendary.
Facebook is a lost cause, so I'll give you that.
UX isn't just user experience - it's customer experience. And if your customer experience is bad, you don't have customers for long.
You can deal with this with hyper-aggressive bully and thug marketing and legal lock-ins. And as a plan, that totally works - until it doesn't any more.
Good UX is cheaper and creates less friction for everyone.
Ultimately, it's just much easier to deal with customers who don't hate you or your products.'