I would say most breeders who are serious about health concerns and overall quality barely break even on a $1500 puppy because of all they are investing in health checks, performance checks, proving their dog has the "right stuff" to be a solid working dog, proving the dog has the right structure etc.
Your puppy's parents may not have had any of these things and you just got lucky. There are plenty of sad stories here where folks got the short end of the stick.
NAPWDA Certified Cadaver Dog
Waiting at the Bridge (italics
=GSDs) (hemangiosarcoma=blue):Grim , Cyra, Toby
, Rainbow, Linus, Oscar
, Arlo & Waggles