Well, HAVE they?
I dunno. I mean, I've been interested in photography for a very long time- once the transition to digital happened, I basically stuck with P&S compacts while mulling upgrading to a DSLR for the longest time...the breaking point however happened when I got to go to this really great (indoor) Q&A event...I took pics...got back and EVERY SINGLE FLASH PHOTO with a person in it had red-eye...and every non-flash shot was grainy and blurry. I just got sick and tired of not being able to get decent shots indoors (or in non-"sunny, blue sky" lighting)...so then the Rebel T2i came out and I got myself one right away. I had the impression that getting a DSLR would improve my photos overnight. Well, shocker- it didn't. I found out rather quickly that if I was going to get the pictures I wanted, I needed to learn to use this thing...and also get a better lens as the kit lens quality was DEFINITELY not $800 better than my Canon Elph.
The main issue was that I had rather high expectations. I guess I was expecting closer to professional-quality photos since I now had what laypeople seem to refer to as a "professional" camera. My point is, I suppose, it wasn't the camera itself so much as it was my working to fulfill this new, higher expectation I had from it that ended up having the biggest impact on my photos.
It involved several trips to the camera store, several hours/days/weeks reading about photography basics and talking to people, thousands of shutter clicks and, of course, thousands of dollars spent on the type of lenses required to meet my IQ expectations. And it's a learning process that I'm still going through right now.
I guess, now I can pick up my iPhone or Elph and under the right conditions, get somewhat better shots than I used to, but having the right camera REALLY helps. Makes things so much easier...BUT- there IS a learning curve that has to be overcome before you get the desired results.