The only known successful attempts at captive breeding of tiger salamanders took place at a university in California a few years ago, (I believe,) and at a facility in Japan (Tim Johnson posted pictures which can be found by doing a search,) last year. But for the most part, terrestrial ambystomids in general, have proven to be difficult to breed in captivity. (Though some have been able to "captive" breed animals in outdoor habitats, which would be considered more farming than captive breeding, however.)
Bait shops, regardless of what they tell you, harvest all of their larval salamanders from the wild. It's cheaper to wild-collect and sell, rather than take the time to breed and rear baitstock. Bait shops would lose profit, because it would cost too much time and money to captively breed and raise animals that are inevitably going to be killed anyway.
A comparable example would be ball pythons. You can purchase a hatchling ball from any herp show for roughly $20 USD. However, those animals are usually wild-caught (or captive-hatched, which isn't much better), which is why they can be sold so inexpensively. Captive bred balls sell for much more, because the breeder spent a good amount of money and time rearing a higher-quality animal.
But I digress. Tigers, like it's been mentioned, are difficult breeders in captive environments and because of their abundancy in the wild, it's more profitable for bait shops and pet stores to buy wild-caughts than go searching for breeders.
This person you mentioned that you "know breeds something like tiger sals" may have collected egg masses from the wild and raised them. That brings up another question - are the tiger salamanders you say he has A. californese? If so, it's pretty illegal for him to have them. (California Tigers are a protected species.)
