Tbf, the WebSQL standard was not well-written from how I've heard that story told. It was bug-for-bug exactly standardized to a particular version of SQLite, which is not a good way to write a standard.
The important thing is - Firefox has been slowly dying for a decade and SQLite has taken over the world.
Firefox is nowhere near dead on my devices!
The issue was that a specific library would be pinned at a specific version for the rest of the history of the web. As good as SQLite is, I hope to hell we're not still stuck using it to handle mining operations in the oort cloud in 200 years.
This is why wasm is great. Webpages can just ship whatever version of SQLite they want. And/or eventually migrate to something better.