I don't know what your financial situation is like, but $5 is a pretty low entry point, given all of the positive reviews (not even including mine). It's also low enough that it may not make sense to release a demo - it might be more work than it would bring in.
I've stopped worrying about spending $5 here and there, given that last year I wouldn't think twice about casually ordering a beer at a bar - especially when it comes to paying for software.
The average salary in my country is $30/day, but it's not so much about that as about the fact that it's very unlikely that I'll like a game, so at $5 per game the expected ROI is negative. I'd like something that can raise the certainty before I purchase (e.g. a demo, or at least an extended trial period).
Too bad Google only allows you to try an app for 15 minutes or so now.
I've stopped worrying about spending $5 here and there, given that last year I wouldn't think twice about casually ordering a beer at a bar - especially when it comes to paying for software.