Your mother-in-law is right. Seed companies do the same thing. They sell lots of F1 hybrids under their own names. A few are good, but many are just another boring tomato with a fancy name. The upside for them is that F1 hybrids don't come true from seed so if you want something like Sun Gold, you have to buy new seed every year.
I think hatcheries may want to try to start using the same model. You won't get a California Tan if you breed two if them. And since you don't know exactly which strains of which breeds produce them you can't breed your own. The problem for them is I really can't see anyone getting as excited about California Tans as some people get about Cream Legbar, Silkies, or- God help us all- Buff Orpingtons.