You don't *have to* , but that's where a big chunk of your business and profits are for a general purpose, all around LGS . Of course if you are specialized in long range rifles , or high end sporting clays , or whatever , different set of calculations .
Do you have to have an RWD to sell handguns over the internet, if you aren't selling them directly to Maryland residents?
I think that is how United started, and then expanded from online sales to the shop in Rockville.