Many of the most successful big breeders also have hustled and marketed to get to where they are. They didn't just go out, buy up a bunch of snakes and boom, successful business! They built it up by spending a great deal of money on original stock, by marketing their animals to all of the best buyers including individuals, and making certain they keep a good reputation not only for quality animals but also good customer service.
Having an outlet for "less desirable" snakes like male normals is a very important part of selling ball pythons. Selling healthy, well-started ball python babies instead of unfed, dehydrated African imports can make a huge difference to a pet store, so many smart pet stores will want animals from the breeders instead of trying to import their own and keep them alive and get them adjusted.
(Note: not all African imports that are sold are sold as dehydrated unfed hatchlings, but it takes effort and time to get them feeding and not many pet stores do that)
It's easy to look at a "big breeder" and fall into some "Oh they don't care about the snakes, it's all about the money!" mentality just becuase they are a BIG breeder and there's some stigma against 'big business' or 'industry'. But a big breeder with thousands of snakes can be just as passionate and very knowledgable about their animals. I've met lousy small breeders too.
Many of the small breeders that fall out of the hobby either lose interest when it's obvious that doing all this ends up being a LOT of work and requires a LOT of patience and you can be wiped out with one random sick snake... or their life changes, either moving for work, starting a family or suddenly not having enough time when they really get into breeding. It doesn't mean they were bad at it or bad people... but that they decided that they don't want to continue breeding. I've been at the ragged edge of giving it up a few times.
TL;DR? Big breeders that are successful put a TON of hard work into building their business up over a long period of time. If you want to do it too, be prepared to put in the same time and effort(and money).