Well, I'm running a 2010 iMac i7, that certainly cannot run Classic, the apps simply were parked in a Folder in Users/Library/Classic, at least that is what I remember, and never got removed. I have a lot of old stuff that I every now and then manually remove. I don't think Apple is too invested in housekeeping unless something actually interferes with the new app or OS. I actually just used Classic for a year after adopting 10.1.5, then had no need to.