They are - it just isn’t instant (revokation only works overnight)
And if they aren’t disappearing for you at all then you might need to get into the rails console.
You might well need to do that to mop up any stray Titles out there too. Shouldn’t be too hard to identify them nor delete the content of the Title field for them.
I’d certainly prefer if the stock Badge queries were set up to revoke superceded badges (as per the SQL tweak above), but that is up to the Discourse @team of course.