Just jerking your chain a bit - I don't even own a two-person tent anymore; just my solo tent. Like you, I don't really like sharing a tent anymore, partly because of the "nature hikes" and partly because, well, I just prefer it that way. The friends I hike with are the same way - we treat all trips as solo trips taken together, and each carries a fully self-sufficient load, including his own tent, stove, pot, and water filter.

Mostly, it's that we like to play with our toys when we get the chance. But partly, we find it gives us some flexibility - if I decide I'd like to sleep by the creek, and one of the others spies a spot up on the ridge, we just split up for the night and meet up somewhere the next morning. We don't split up often, but it's nice to have the option.