Great point, can totally see where you are coming from, as you have to make what sells and not always what people ask you to make. i do not think i have met more than 2 or 3 people who collect the Alamo range, but multitudes that collect Naps, WW2, Vietnam, etc.. Plus i looked back and those sets have been out a long time, they certainly took a long time to sell out/retire. Long time to hold stock, a lot of money tied up.
I always imagine your warehouse to be a bit like the Toy soldier collectors version of the a kids sweet shop, if you let many of us collectors in we would get a headache from the excitment and many would probably have to be dragged out shouting and screaming.