If the community isn't based around an interesting enough topic, it simply wont succeed.
The rules here can seem a bit strange.
A community for people interested in backyard chickens can succeed where communities for frequent flyers can fail.
So how do we know if our topic is interesting enough to build a community around?
Simply, do people already talk about it online or offline? If they don't, you're going to have a hard time building a community around it.
p.s. 100 people mentioning the same topic 50 times is a pretty good indicator they're interested in it. 1000 people mentioning a topic once is not. Knowing the difference is important.