I think the words “commercial” and “non-commercial” get misinterpreted.
It’s hard to sum up the breeding and racing industry in a few words on the internet; and attempts to do so often generate more misconceptions.
But to try to answer your questions while not generating more misconceptions, I’m going to back up for a moment and point out that the sales market drives most breeders’ mating decisions. This is because it is EXPENSIVE to breed; and it costs just as much to breed & feed a “cheap” horse as it does a blue-blooded one. Then you have to consider the cost of the mares themselves, stud fees, sales consignment, etc. A breeder who can’t sell their horses at a profit is going to find themselves bankrupt in a hurry.
In general, the buyers in the North American market want precocious dirt horses because that’s where the money is in racing. They want flawless horses who tick all the boxes, and when they find that, they are willing to spend a considerable amount. But buying racehorses is a risky business, and when a horse offered for sale doesn’t tick all the boxes, the buyer is increasing their risk. So buyers shirk from risky horses and gravitate towards those who are the whole package. Wouldn’t you do the same if you were spending that much money?
To attempt to answer your original question:
If a young sire’s first crop of yearlings hit the sales and they aren’t ticking all the boxes, buyers are going to respond in a lukewarm fashion. It may because the get are smallish, awkward looking, poor moving, have vet/conformation issues, or even just a subpar first book of mares (which isn’t the stallion’s fault at all). But whatever the reason, poor sales figures from a stallion’s first crops will cause a portion of mare owners to shy away from the stallion to avoid the risk of financial loss. Plus, every year a stallion stands, he is facing new competition from the next group of first year sires, who draw more mare owners away.
If this happens to a stallion, sometimes they are redeemed when their get start running and prove valuable. Other times, foreign interests realize the potential and are willing to pay more money for the horse than he would earn staying in North America. Or, the stallion stays in North America and drops in class until he finds a niche market (like a regional program), or another job entirely.
Other stallions “take off” right away because their first crops consistently tick all the boxes and appear to be the whole package. And buyers and breeders alike get excited (often more excited than they should) thinking they are getting a piece of the “next big thing.” Sometimes it works out and the stallion really is the next big thing, other times they fade into obscurity when everyone realizes the foals were awfully good looking but can’t run a lick.