I checked out the bloodlines pages-- those are good lines, but very old-- 23 of the 28 listed were foaled between 1875 and 1949, so they would be pretty far back on the pedigrees of registered Arabans alive today. The other 5 featured were foaled from 1950 through 1970, so still a few generations between them and Arabians alive today. These bloodlines were generally also very prolific-- many, many Arabians in the USA and Canada trace to these same horses.
I looked around on the rest of the site and it appears that these folks show and promote their stock quite actively, and most of the horses on their sale page were already proven in the show ring or as producers, or offspring of proven parents. It also looked like the Arabian stallions they were using were all over 16 hands, and all their mares are listed as between 15 and 16 hands-- its hard to find that kind of size in a purebred Arabian.
So yes, they have used good bloodlines, but lots of breeders use those same lines and don't get high prices-- my guess is that the showing, proving and promoting they do adds value to their horses, as well as allowing more people to see them "in action"---and as well they are breeding for a size hard to find in their breed.
My $2 and 2 cents