I think Mojaves have been affordable for a longer period of time, when compared to Fires. I would say more people have had a chance to buy and let a female Mojave mature, vs. those that have Fire females or Sulfur females.
By a show of hands, who has Mojaves, and who has a Het Black Eyed Lucy? Which did you buy first, do you have a female? I would bet more people bought Mojaves or Lessers before Het Black Eyed Lucies, and I would bet fewer people have female ADULT Sulfurs or Fires.
Plus, you can combine the Het Blue Eyed Lucies, have a Mojave, and a Lesser, one male and one female. That is more fun than buying a male and female of the same morph.
Dave