Part of the challenge here is a general lack of understanding by not only the general public, but Littleton town officials on both federal and state law and the interactions between the two. Town officials have said in multiple forums and multiple times that they would shut us all down if they could because they think we are just gaming the system.
The ATF has ruled that a LOT of activities require one to have an FFL: Selling too many guns at gun shows, being a writer that gets guns sent to them to evaluate, etc. In a free state, the individual would get their FFL with their home as their place of business. They would become a kitchen table FFL. This is the practice throughout the country. MA prohibits being an FFL at your residence and demands a separate location/address (ok, there are a few exceptions to this, but lets run with this for now). Another common type of business that does not require a place like the Mill (outside of MA) is someone selling on the internet like Armslist and Gunbroker where all your sales are shipped to another FFL to run the background check, etc.
When you apply for the FFL, you are required to apply for all required state licenses. One could argue that many of these activities do not require a state license, but that is potentially a very fine line to walk. Also, if you are selling out of state, you want to sell items that would violate the MA AWB and the MA magazine capacity restriction. In MA if you have a MA Firearms Dealer's license, you are exempt from the AWB and the magazine capacity limit. This says that even if you never sell anything to a MA resident, you want your MA dealer's license so you can legally possess and sell new ARs, 30rd mags, etc.
Federal rule and state law cause the Mill and places like it to come into existence in MA. It is a necessary construct to satisfy the ATF requirements for a FFL and the MA requirements for a separate location and a dealers license for exemption to the AWB and magazine capacity limit.
I am certain no one in Littleton understand this issue and why the Mill exists. If you take it at face value, there is no way that 50 businesses selling firearms can successfully compete with one another at the same address. But that is not what is happening. Only about 10 are truly active with local retail sales. The rest all fall into other categories of business or requirements to have their FFL. One guy is all about pre-ban ARs and AKs and does everything online. One guy is all about doing research into silencer development and technology. I could continue the list of other businesses that are doing things other than major retail.
Again, if we take this on face value, the powers that be in Littleton understanding why they have so many dealers should make the issue go away. This is not gaming the system but finding a solution to a complex problem caused by Federal rule and State law that are nog aligned. Unfortunately, I am not optimistic that this will change anything