I shoot with a Conon XT and I only own the stock lens. Not because I dont want a different lens, the stock one is pretty bad. I just can't afford to throw down 500 bucks right now. When I shoot with my film SLR I will usually bring at least two lenses along for the ride. I think people buy the DSLR's because of the following
-if they ever want to upgrade to a new lens, they can.
-Higher resale value.
-Gets out-dated at a much slower rate than a point and shoot.
Who cares? More people buying DSLR's means a bigger market, bringing more competion and lower overall prices for everyone else.