I remember DOS programs just fine. In fact, thanks to today's technology, I don't even need to be old enough to remember them, I'm still living with some of them ;) [slight exaggeration sure, but not excessively so IMO]

My point wasn't so much the advances that 3.1 and 95 were or weren't, it's that each had fairly impressive improvements in the UI, but were still veneers bolted on to the last OS. I can appreciate them wanting legacy support since their cash cow is the business sector, but in doing so they limit their scope for advancement.