It's great that you have a supportive sponsor and a regular place to meet and enjoy. I do not know what midwest america is like but it must be very difficult commuting and traveling to get together.
Ouch... but thank you for sharing. I don't know if I can help at all but I will just give thoughts.
Does your area see each other more or less as friends or just acquaintances who play similar games? That kind of attitude can hold a lot of difference.
Like with some places, people who attend treat the event, venue, and other people as they are customers entitled to do what they do because they pay a fee to take part.
Maybe for some people it's a change of culture, getting new and old people to respect the terms laid out by the people who work to organize the event. The simplest gestures can really go a long way in getting people more comfortable with one another.
Suto and GGXrd can be the main games where a majority of people partake, communities will always have a main attraction where most people devote to. But other side games can be really helpful even if it's just 3 or 4 people.
Outside of brackets so long as you have maybe at least 2 people playing a game on the side someone might eventually ask or want to take part and continue to do so.
Gundam here interests people but people don't play it because it is different from other games or they don;t know what it is. Playing casually usually catch their attention and if they try, sitting down and teaching them the basics and having just fun casual matches. Those people usually came back wanting to play again, especially since it can be prohibitive to get to play a game like Gundam outside of the local meeting.
It doesn't have to have many people play, just a couple at a time while everyone stays on the main game and sometime you get gradual interest.