That only applies to things you want deleted.

In the short term you're absolutely correct.

In the long term everything suffers from "data decay". It's just too hard to keep old files around forever.

E.g. there were comments I made on Usenet many years ago. Google has previously attempted to preserve those, but they seem to be fading away into the ether. That's okay by me.

It is, in fact, really hard to be ablet to delete data from an online service, while also not raising the chance of losing it accidentally. But if you treat it as an engineering goal from the start, it's possible. (Disclaimer: I work for Google, and we work very hard on this.)