I had the same experience after Classic closed down. I had four accounts. Whn everything moved to .net, I chse to keep my .com pages. Now I can use FTP to dit and it is much easier.
When Classic closed I was told that "in a couple of months" the old pages would be removed. Not so! Just checked and my first "old" pages, the really old ones that tied to user IDs, are still active. So they may be there forever.
Old and new pages are mixed on the same server.