Earlier quoted context omitted.
They absolutely should and this should be considered when adding new features. That's called having a stable platform that others can build upon.
I think you don't know how much has already been removed and we're absolutely fine without those features.
(For example: was never in WebKit or IE; Web SQL was never in Firefox or IE.)
Well, OK, I’ll count SharedArrayBuffer, which shipped across the board for a couple of months before being disabled for security reasons, and took up to four years before being shipped again, in slightly restricted form.
I wouldn’t count applets or plugins like Flash, because they weren’t really part of the web platform, and they also still work in theory, it’s just that the plugins in question no longer exist.