Simple is different for everyone. Simplifying shouldn't have to mean selling all other gear for the sake of one piece, although for some it might mean just that.
I've been on this simplifying -> smaller trend for a few years now. Coming from a large kit of medium format equipment to what I carry now, I wish I'd been less timid about scaling down and had skipped a number of intermediate steps.
What I've also noticed is that I'm quite happy with carrying just a camera and a single lens around to the point where I've been shooting one camera one lens for the past two months. Not only happy... but I prefer the limitation, I like that the camera is always with me and that it's always the same camera and same field of view. I think the self imposed limitation is helping me in a variety of ways.
My larger small bag, the one that can carry a couple small bodies and five or six lenses, hasn't been carried in months. My very small bag that fits only my phone, camera/lens, and my wallet - that one has been with me constantly.
In fact I've enjoyed this new minimalism (for me) so much that for my own personal photography I'm going to continue to shoot just one camera, one lens (35mm), for all of 2013 and am seriously considering disposing of a bunch of gear that I know I can always get again if I decide I want to down the road.
For me this feels like a revisit to my teen / early adult years when I had purchased a Contax body and could only afford one Zeiss lens. I shot that for quite a long time before part time employment in between school allowed me to pick up a second and then a third and... well you know. But I continued to shoot that first lens more than any other and looking back at my chromes I see that the restriction wasn't a bad thing at all. I've come full circle I guess.
