Because statistically (I can’t find a link right now) or the past decade (hmm) the gun industry is going through a thing wherein less and less people in general are buying A gun.
But there’s an increase in individuals buying many guns and accessories. So there’s a less diverse spread of people buying guns for hunting or shooting at the range and more people buying guns solely to help them fantasize about hordes of non-white people rioting outside their home so they can shoot them. It’s part of why the NRA attracts and caters to a certain crowd, those aren’t the only folks buying guns, but they have the highest amount of individuals who will be dropping $$$ on guns and gun stuff for the rest of their lives.
The AR-15 itself, its popularity is a thing because it’s encouraged by the NRA because it’s profitable long term - tons of cool looking tactical accessories get made for it that people love.
Part of why white supremacist mass shooters flourish in this country is because a very small number of people in a few companies want to make more money off add-on impulse purchases.
So the idea of actually playing a game with your gun? That’s like the farthest possible reason from why people get lots of guns today. Otherwise there’d be air soft guns everywhere instead.