I think it's fairly obvious that just because you have expensive gear, your not automatically going to be a good photog with excellent quality photos. But there are certainly other reasons for getting expensive gear than just the end result. One main one that I think of is using the tool, or the act of taking the photos.
I got my 40D just over a year ago and before that had a canon s3is. At first when I got my 40d I was a little bit disapointed with my results I was getting. It certainly was a little different than the point and shoot, I don't want to say more difficult, just different.
I'm fairly happy with the results I'm getting now, but still have tons of things to learn. But even when I wasn't getting great results on a regular basis when I first got the camera, the act of taking pictures was so much nicer and more enjoyable. Which led to me wanting to use my new camera more and eventually figuring out how to use it to achieve decent results.
Looking through the viewfinder and seeing down the lens instead of looking into the viewfinder and some tiny little lcd screen. Being able to turn the iso up higher than 200 and still get usable images. Shooting action shots at 6.5 fps. The list could get pretty long, but you get the idea.
I also drive a mini-van, I can drive to my grandmas house in about 2 hours going 70mph on the freeway. If I had a porsche I could also get to my grandmas in 2 hours going the speed limit of 70mph, which would you rather drive?
I say if you can afford it and want to buy nice gear, have at it, it's enjoyable to have/use nice camera gear even if your still learning to get good shots.