Unfortunately, any higher and they will never sell. I get some complaints about the price now, but people's idea of aquarium value have been warped by the GPD sale. The glass box is a loss-leader of sorts. Theory used to be that once the customer bought an aquarium, they would need a filter, light, heater, etc. but these days most buy the tank from you then everything else online. My store lives (and may die) on dog and cat food.
Nothing good happens fast in an ecosystem.