Second, that site looks at all time; divisions have only been around since 1991. So you'd really need to look at a more current version. I'd imagine you'd see that in version that looks at performance since '91, things would be a bit more equitable. Florida and UT would certainly be better, given performance since '91. Missouri and SC may also fare a little better.
I think it would be closer based on a more current view. But I'll admit that based on what you presented in the context "all-time", the conference is less balanced than I would have thought.
The site has flaws, obviously, for instance Princeton isn't exactly a football power anymore. South Carolina is one program which, if you look at other indicators (like attendance) is more powerful than that ranking indicates.
Having said that, I prefer the long view vs. the short view. The short view might tell us that Boise State is a football power for example, but they're not, they've just had a few good years against cupcake competition. On the other hand, TCU was a football power decades ago, and they kept enough infrastructure in place to be able to join the Big 12 and not suffer competitively. The 32 ranking all time is pretty informative in my mind. I believe as long as someone is around to keep things up at all, a program has the capacity to return to prominence after even decades of mediocrity.
I do agree though that if shrunk the perspective, things would be more balanced certainly, but I love the tradition of college football and the fan bases go back for generations. We saw how Texas A&M did financially once they had something to get excited about, but really Arkansas, Ole Miss, these are programs which won't settle for being happy they got in a bowl game. There's always going to be a lot of pressure in the SEC West and a demand for results, and I don't want to go in depth on that here, but it certainly appeared as though Ole Miss decided to buy their way out of being mediocre. I don't think Kentucky, Vanderbilt, or even South Carolina has that sort of pressure, and I suppose that's one of the more telling aspects of the all time ranks. It indicates the roots a program has.