Uhh - registered herds need fertile, long lasting, pound producing females also.
You have a very biased opinion of purebred breeder's herds. Not all are alike. Yes, there are some PB breeders that are more interested in papers. Not most. I have more cows related than sires of the cows. With AI, we have a vast selection. Lots of outliers to pick from and lots of spread bulls. Not everything is painted with one wide brush.
If a bull is producing great sons, why not keep breeding to the sire - unless he is not producing great daughters. I breed every cow mated for the best female calf I can get. I don't breed for bulls. If I get good ones, great - I don't genetically breed for one.
Females is where the future is - and my money makers. Males are cash flow. All sold by October.
I am not a rarity. Good breeders are good breeders.