The only thing you need for a successful gaming community is for the following two criteria to be filled:
1.) A game exists.
2.) People want to play it together.
NOPE.
At a minimum, a successful gaming community needs:
1) A game exists with a comprehensive (though need-not-be complex) ruleset that caters to casual and competitive players, pulling interest from as many people as possible, run by a company that is as passionate about its product as the players, and responds to them appropriately.
2) People want to play it together.
3) A store that puts in the immense amount of time and effort to support the game, stock the latest items, stock all the other items, take special orders for customers, make tables and accessories available at a moment's notice, host events, etc.
4) Players who put in an immense amount of time and effort to support the community, preferably those players with basic social skills, determination and a willingness to teach the game as a game.
5) Luck, because it only takes one bad apple to spoil things for lots of players, or for the store to be in the wrong location, or an economic downturn...
But really, it's the complete lack of acknowledgement for #3 and #4 that chaps my ass. Do you even community, bro?