there's more ground to cover in answering that question than there is room on this forum but, in a nutshell, AKC shows are made up of judges, handlers and dogs. The judges are people who have usually been handlers or big-time breeders before they become judges and therefore have some loyalty to handlers and other breeders. That's just human nature.
Add to that the fact that beyond showing dogs in the classes to get them to finish their championships, the major handlers have "Specials" that they show in Best Of Breed competition for national ranking. A Special is a dog that has already completed its championship. These dogs get advertised heavily and the judges who put up these dogs get publicized in all the dog publications.
So, now we come to a series of shows called The Florida Circuit: 15 shows over 18 days all in the Greater Orlando area. These are pretty much the only shows taking place during the first 3 weeks of the new year so all the big-time handlers plan to come to Florida with their class dogs and their new Specials to get the New Year off with a bang. In this type of environment, there are enough shows and enough handlers so everyone can get a piece of the action either in the classes or in the Specials ring. But the biggest names always get the most wins. It's what we in the dog show world call "an amazing coincidence"!
With all that going on, it's difficult for less well-known handlers to get a decent piece of the action. Except in certain breeds where owner/handlers are more common than professional handlers such as many of the Toy breeds, Whippets and some others. Now, you may ask, does it ever come down to actually judging the dogs? Yes . . .to some extent. Some judges actually do judge the dogs and it doesn't matter who is handling them. But keep in mind that judges get selected for show panels based on the number of entries they get and the most popular professional handlers can come to a show with up to 25 dogs in various breeds. So the judges know where to apply the butter on their bread.
When you get into Best Of Breed competition and then on into Group Competition and Best In Show, the better known the handler/dog team is, the better chance they have of coming away with the big prize: Best In Show. For example, in the first series of shows in Deland, one of the top dogs in the country -- a Sealyham Terrier -- took a Group 1 all 4 days but didn't get a BIS. A Rough-coated Collie took 2. The handler of the Sealyham was none too happy.
Once the shows moved to Brooksville and a different panel of judges came in, the Sealyham won 3 Bests In Show and the Collie didn't win another. Irony? Perhaps but I suspect it was retribution for the handler.
The politics of dog shows is simple: you feed the folks who help you succeed. Just like politics everywhere else. To succeed in this game, you need good dogs and you need to know how to win with them. We learned that with our first show dog, Annie Fay and were able to finish her despite the fact that she wasn't the type of girl that was finishing in those days. We found the right handler and we showed her to the right judges.
I've never Specialed a dog at the National level -- Rowdy did his share of winning in Best Of Breed and at the Group level but we never could afford to try to rank him -- but we handle the advertising for a bunch of people who do. It's a tough game and you have to have deep pockets and thick skin to play it successfully.
I hope that gives you some insight into the Show Game. Watch the movie Best In Show to get some hyperbolic clues about what goes on.