Topps isn't the only company that counts. "Major Release" is the key. On TCDB, Major Release is defined as "National, pack-based or factory set release by a major card manufacturer"
For Canseco, that's 1986 - Donruss and Fleer. For McGwire, it's 1985 - Topps.
I'll never quit collecting entirely, but I am downsizing. Check out my COMC store and help me thin out what I don't want so I can buy cards that I do want. See something you like? Send me a message on here, and we can knock the price down quite a bit. I'll even take a bit of a loss if it means getting you a card you really want.