There are a few people who like collecting Generation 1 Dragons (No Parents) and geneing them up. Mainly people like me who LOVE Gene projects.. >w>, The better the colors, the better they sell for.
This here, I got lucky when hatching her:
She'll look like this when I'm finished:
I just finished this one:
This is what she USE to look like x-x (the egg she came from was a B-day present sooo I hatched her on my bday and made sure she'd come out pretty!)
Though most people won't save an ugly Gen 1... they don't want to gamble with the Tri-Color Scatter Scroll.. (I got lucky with that gamble >:x)
Unbred dragons won't have a long list of children (and possible exalted Unnameds) and it also means they haven't had multiple mates (I honestly don't know the real reason, I'm just assuming here.. I don't pay attention.. x'D)
I think there also might be the idea that Unbred Gen 1's can make good replacements for your Pro-Gens (Starter dragons). Since you can't make a second account, not even to start over.. those who do wish to start over, sell everything they have.. all their dragons, items everything and exalt their progens and just get unbred Gen 1's to use as Pro-Gens instead ovo
Gen 1 Imperials on the other hand... Woo... The breed change scrolls for that were Kick Start items so other than finding a Imp Scroll seller, or finding a Gen 1 Imp for sale.. They are probably the ONLY Gen 1 Breed where it doesn't matter if it was bred.. getting your hands on one is that hard... though if it's unbred it will be even MORE expensive than it is now.
(Low Number ID dragons also seem to sell well apparently >->, dunno why..)