I dont get it. These guys retire or whatever and then they dont even try to maintain any muscle. It doesnt make sense UNLESS the doc said it will kill them due to other health reasons. I mean most of us actually like to train. I know they cant stay at 250 plus pounds but they could stay around 200 with muscle. maybe they are just burned out mentally and physically to workout but yet they still do videos or expos or whatever. hell stallone looks awesome and hes in his 70s.
Dennis and his downsizing is addressed here at the beginning of this video, in that discussion between Steve Kuclo and Dennis:
^ Although it isn't mentioned whether or not Dennis is now no longer bigbychoices, or if he is because he had no choices [possibly due to a neck injury that Getbig's own Van Bilderass alluded to above]. Or maybe he got small because someone give him the wrong advices.
I always find it funny when people say "He looks good - looks healthy", which I always find is code for saying that a retired pro got smaller.

In 2012-2013 when Jay "shrunk" down to 260-lb [which is technically true, as his previous offseason weight was normally in the 295- to 310-lb range], he said that a lot of people were telling him that he was "getting lean", or that his shoulders were looking leaner than usual. All veiled ways of telling him that he was getting smaller.
But in the end, it was good for Jay to do that, and to be honest, I think he should get even smaller than he is now.
Unfortunately with a lot of pros, when they competed at 5'9" and 255-lb, and were offseason at 300+, they have a tendency to look a bit strange sometimes when they are 250-lb at their normal offseason bodyfat.
In the case of Ronnie and Jay, they would look like they need to be inflated, even if at 240-lb.
Kevin Levrone was THE exception to that rule - he could be 180-200-220-240- or even almost 260-lb in contest condition at 5'9.5", and he looked good at all of those weights. Whereas Ronnie Coleman at 250-lb has big hands, and other remnants of his former size, and just looks like he needs to fill out. I think that factors in to some of the body dysmorphic issues that some retired pros have, which prevents them from downsizing as they probably should, for the sake of their health.
I think Generation Iron's new movie "Bigorexia" is out this month, sometime pretty soon. It probably talks about this thought process, among recently retired pro bodybuilders.