While I agree that larger breeders have more resources available, I disagree it's simply about cash-on-hand to purchase traits.
While that is certainly possible, it's more likely that larger breeders simply have more, and better, stock available to research a new trait. In addition, when it's a race to discover and exploit a new trait, larger breeders have more practice at managing several lines of development at once.
In fact, one could argue that a smaller breeder/collector has an advantage on the costs because they are spending less, daily, on KittyCatS and, so, could have more mad-money held back for large purchases.
My point: the size of one's stock does not indicate any profit on sales of KittyCatS, or sufficient profit to purchase new traits or large numbers of collectible starters; it could actually indicate money is going into current lines leaving less for such purchases.
From the company's point of view, though, those larger breeders are their bread and butter; and many of those large breeders are already fully committed. Putting out a large collection could well backfire and cause those larger breeders to reconsider their current level of commitment. Remember, no matter what else is sold, food sales are the core income and anything causing large numbers of the larger breeders to reduce food purchases will hit a lot harder than whatever paltry (by comparison) income they might see from sales of the collection itself. That is, unless the goal is actually to entice larger breeders to pull back, and replace them with .. what? a 10-to-1, a 20-to-1 ratio .. of new, smaller breeders.
This is not saying the company should cater to larger breeders. Rather, they should carefully consider all aspects of their decisions and strive to balance the various needs. And, often, the goal is the 'least unpalatable' rather than 'best'