I do not think the "house on your back" even has to be minimal. Backpaking is getting from point A to point B, with an overnight stay, as a self-contained unit. If you want to literally haul the kitchen sink on your back, more power to you! I do not think it matters where you go. You can even do urban backpacking. Some places there are few people, some a lot. Again, I do not think it matters. Being a "self contained unit", brings up the qusetion if trekking from hostel to hostel is real backpacking. I think that is a borderline issue- maybe sometimes OK (such as hut-to-hut in Canadian Rockies, but maybe not hostel to hostel in urban Europe). Is road walking backpacking? Depends. Some roads are for all practical purposes just like a trail, others literally a highway. Another question - are you "backpacking" when you are primarily climbing, but need to set up a base camp? Do people who climb El Capitan backpack? They are self contained, carry thier house in a hual bag - not on back, (but believe me, it takes a good deal of effort to lug the "pig" up the cliff) go from point A to B, "camp out", but do not "walk" - they climb!

Studying the natural history, geology and botany of an area enhances the experience, but I do not condsider these the essence of backpacking.