I might be mistaking things here but I believe that Apple's CoreData and Android's equivalent are both powered by SQLite under the hood.
Messages on macOS stores all your message in a SQLite file under ~/Library/Messages/chat.db
macOS and iOS both use SQLite pervasively. There's tons of little databases all over.
Chrome uses SQLite heavily for history, cookies, bookmarks… etc. So does Firefox.
SQLite is everywhere. :)
It must be easy for SQLite developers to apply for jobs. Let me into your company, you've already let me into your home, your office, your data center, and your pocket.
As amusing at it is to imagine, their team page only lists 3 developers[0], so I bet that turnover does not happen particularly frequently!
It's everywhere to the extent that I find it hard to believe it's not lurking somewhere on a default Windows install. I would very much like to be able to say to people "do not use excel for that. It will make you cry" and not have the response "corporate IT won't let me install anything better."
It definitely exists within Edge, as that's Chromium-based. Not sure it's available in a standalone form, though.