Wow. I think I'll kick in here with some observations. I also note I owned a game store for some time, am an older, retired, military veteran and have three sons, all of whom play some or several miniature games.
I, as a Game Store owner, sold a hobby, not a game. That is very important to emphasize and make sure it is understood. Miniature or table top gaming not a game like Monopoly, Risk or Cataan. It is an entire hobby, in which you decide how much of your time and money you will invest in it. It is not for everybody, thus it may not be viewed as "mainstream" like knitting or sports card collecting.
When people came in my store I always talked to them and asked lot's of questions. I always had at least ONE game out and set up for a quick demo. Most of the new people wanted to know what it (Miniature table top gaming) was. Simple answer, it is like Chess but different. Of course I would explain then it was a hobby.
I would invite them to try a demo right then with me, or ask them back as a guest on game night.
I was also blessed with gamers that loved to help and allowed any newb to play a game with them to learn the ropes. Or even assist in painting assembling, which of course, usually went on all the time.
I no longer own my own store so now I have more time to participate in the hobby, (there is that word again), I am a Henchman, run classes on painting and terrain building, though I am by no means an artist as some here are, but I get the basics of have fun across.
So there you have it, TTG/miniatures are not for everyone, and I like the fact it is not.