Well Bobbi, first one puts out a daylily that looks somewhat different.
Some become registered. People like the different look. Then when
some of these daylilies are looked up, not many garden photos can be found.
Some seedlings are sold from the field or whatever. People like what they get.
The seedlings are a less expensive way to get the look.
Some seedlings go on auction. People love the look. Many want the look.
Then they sell great, really great, and then really, really great.
Why go through the time and paperwork to register them when they sell so well without
it, and still be able to keep the best for hybridizing.
I think the short of it is simply supply and demand.
JMHO, of course.