We all have as many individual reasons as we are individual people for participating in photography. (Even though we may use similar words, like hobby, the meaning of hobby is as individualized as we are.) I wrote a bit of a contrary commentary just to show a different side to collecting different systems. I still see my hobby as I did when I was working news. Seeing and consistently capturing 'The Shot', the 'Exceptional Image' is all that is important. It would drive me crazy if a competitor on the same story "scooped" me with a better picture than I.
If we are on this forum for our own individual reasons, most of those reasons revolve around some need ... praise, constructive criticism, education, photographic improvement, sharing our lives and in particular the photographic parts of our lives with like minded peoples.
Okay, now I'll try to bring it all together ... I love cameras. I have a small collection of cameras as momentos and curios. In the last few months my fingerprints are on so many Leicas in so many camera stores ... you get the idea. But I never purchased. (ala Antonio, it would not be a responsible use of my resources.) But I have been buying µ4/3 gear, spending money like a survivalist in a canned food store. The difference being that I knew the µ4/3 purchases will help me to capture the Exceptional Image. The Leica gear, while being fun, really would not contribute to better photography. I also knew that using the same system, day-after-day, would put me higher on that learning curve where the camera an I would act together as one, as a team and hopefully creating a synergism between my eye and my equipment. There is much to be said for Henri Cartier-Bresson's statement that your first 100,000 photographs are your worst. (Henri was a co-founder of Magnum, and for nearly all of Cartier-Bresson's career, he shot with a Leica and a 50mm lens only.)
For me and my experiences, "better photographs" is the principal reason to purchase equipment. But focusing on hardware instead of the image will retard one's ability to consistently capture the exceptional image. Many of us here want a balance between the fun of collecting hardware and the fun of the photographic experience. And that's okay, but that approach will dilute and slow the raising of your consistency rate, the ratio of keepers to trash . Every time I toss a camera around my neck, I have a passion burning to see and capture that exceptional image. While collecting different systems is fun, it will not significantly help you become a better photographer.
Gary
PS- Now for the disclaimers:
1) Specialization may require/demand different systems. I understand that. A photographer may need a special camera system for ... underwater, or astro, or video. That's different than my $.02 above;
2) There is much to say for shooting/developing/printing film, as that broadens one's understanding of the photographic process. The same argument can be made for using different systems for taking pretty much the same images. But I really don't see this broad approach as an efficient methodology to honing one's photographic skills towards the ultimate goal of consistently capturing the exceptional image;
3) I am speaking only for myself with no expertise of knowing what works for others; and
4) I am speaking of what I suggest as a path to attain 'professional' level photographic skills and images. I think that most of us here would like that level of skill. I recognize that taking the fun of collecting out of the photographic process doesn't balance out the photographic experience that many enjoy.
G