I do believe that the amount of equipment you own is directly related to how good of a photographer you are. For example, I'm one of those that is approaching the 250 camera mark, and even with all that stuff, I suck! So the more you have, the worse you are, simple.
But seriously, I really enjoy 'flipping' cameras, trying out different things, and selling when I'm done with them (usually a roll or two). I do have my main stable though. Those are the ones I may not use all the time, but are not going anywhere anytime soon. Different cameras have different purposes, IMO. Sometimes I want to go 645, sometimes 6x6, or 6x7. I have specific setups for each of those formats (as well as 4x5 and 35mm), and each of those systems does something, or has an ability the others don't. It could be that with the 645 system I can use the fastest MF lens made (Mamiya 80mm f/1.9), as an example.
In my case, much of what differentiates one from another is simply an accessory/lens/back that I was able to get for that system, and not for the others, so if I need that application, I have it, but only in that system. Another exampke is a Polaroid back. I only have a P-Back for my RB67, and that's why my RB is my 'potrait' camera. For light travel, it the Yashica 124G, for general stuff it's either the M645 or the C330. For just snapshots, its the GA645.
I'm in both schools on this; I'd love to get down to a relatively small kit, but I have too much fun trying out different things. With the way prices are nowadays, I feel this is my chance to try all the great gear from my youth that I had no chance of being able to afford when they were new.
I'm the same way with film if you were wondering. Although developer, I'm pretty much stuck with D-76 as I bought a near lifetime supply for pennies about a year ago.