I can understand that, and my own photography is much the same way, except the Hasselblad gets a lot of mileage for serious work too.
The way I see it I feel kind of connected to the Hassleblad and the Leica. When I use those cameras it's as though they are not an obstruction in my work flow anymore, but more of a direct link between the subject matter and my brain. It feels that way when I photograph, and I can sort of sense the entire work flow rush through my blood as I compose a shot, what a print might look like. With these cameras it feels intuitive, like an extension of my senses, and out of the cameras I own they are the ones that gel with the way I work. As soon as I pick up a different camera, I have to actually think about what I'm doing, and that does screw it up for me - royally. As soon as I have to think about what I'm doing, my 'hit rate' of good frames per roll goes down. So, the conclusion is that it simply doesn't make sense for me to get a different camera, which relates back to your comment of admiring the cameras for what they are, but when you want something to truly use, you use what you know the best.
Thomas, totally agree, when I handle and use the M2 it feels like part of me. Even when using the gIII I have to think about the difference, thus destroying what could be a Zen moment. That may sound to some like pretentious crap, but to me it isn't.