My suggestion is this make it so only associates of families have usable access to guns.  This would be the lowest rank to be able to obtain the use of a gun. You earn your gun  normal like we do now doing crimes , but it has a trigger lock in  a sense till you join a family.

Cons:

It will take a little longer to build your gun.

Probably more but the only one that came to mind.

Pros:

Reduce people making accounts just to one percent someone

Reduce the fear of new players among the older player who have created a paranoid mindset

Adds an element of actual Mafia hierarchy. In the Mafia you don't have a gun until your upper gives you one and gives you the permission to have a gun. This was the first sign of trust from the uppers. 

I do appreciate your suggestion, and considering how you want to play this game -- understand where it is coming from. Nonetheless, I strongly disagree. 

First and foremost, This is America. You do not need anyone to give you a gun for you to have a gun. Whether you want to own one legally or decide to buy it from a shady character with a scratched off serial number, it is easy. You don't need to be part of the Mafia to have a gun or to shoot it. 

Second, you don't need to be part of the mafia to make money. On the other hand, however, you will be expected to join them in one form or an another, because you are making money. If you run a loansharking scheme in Area X, controlled by Family Y, you will need to offer a cut. (If they do not run their own scheme already) That effectively makes you an associate. Alternatively, you either a) get beaten, or b) bite a bullet. 

You can not have your cake and eat it, especially in a world of thieves and criminals. If you want to get richer, you need to make some select others richer in the process as well.