An update earlier this year made it so Connect no longer deletes old layers when it published a new database. This is crazy frustrating because there is no clean way to differentiate which layer is the newest "live" version of the data.
If you want this feature, fine. Just add a toggle to Connect's publish screen so this feature can be toggled off and the old database is deleted...
I've lost a ton more data thanks to this change then I ever did from Connect wiping out a database. It's just silly.