Getting a plain yellow from eyed parents seems pretty normal to me
Here are some of the ancestor plants behind the two eyed parents of the yellow seedling:
The eyed pollen parent, Casper's Revenge, was created from pollen off of Fantastic Fringe (so Fantastic Fringe is like a grandparent to the seedling):
Like its namesake, Casper's ghostly unseen genetic instructions can pop up in a second generation, or many generations, later ... in my family, that's just like some of us getting Great-Granpas buck teeth, Great-Aunt Mirtha's large ears, or Cousin Eddie's adorable dimples.
On the other side of the yellow seedling's family (eyed Dragonfly Dawn) there are lots and lots of yellows, and not that many have full-blown teeth:
So, buying seed can be a gamble, especially when they are from cultivars that seemingly have no parents
And, I agree about ebay ... way too easy for nomadic sellers to offload ditch lilies and leave town years before they would ever flower. If an LA seed seller is known, has a stable land presence, and has some history of dependence on the community ... and if the seeds actually have a parentage to research so that you can see the range of blooms you might expect, then as long as the seeds are not in the end as expensive as buying a look-alike parent or grandparent fan ... it may be fruitful to pursue. And, sometimes it's just f-u-n to gamble and watch the parade of sweet seedlings that result! But, if buying newer seeds is like dinner with Michael Douglas and gets priced so high that they are for bragging rights only, I'd much rather have soup and crackers with Kirk, (buy the parent cultivar for a song), instead!
For me, the cost of seeds I'd be interested in have always met or exceeded the cost of full-grown look-alike relatives that have a track record of throwing offspring with the attributes I'd look for, so I just buy the inexpensive relatives, but hope does spring eternal on the LA, and there can be a lot of joy in just getting seeds from a particular cross. And, for those who are hybridizing on a very large scale, its also a way of mixing up the genetic pool and pulling out whatever may inject some new vigor or characteristic into their program.