The cost is prohibitive for me, yes. It's not just that the hobby is too expensive relative to my earnings, it's also that there has been such a quick change from sixth to seventh edition that I found that I could no longer justify spending such a large amount of money, in relative terms, in such a short time period. It also didn't help that read through the new rules put me off straight away, as I didn't, and still don't, like the direction in which they have been taken.
If you like the rules and play regularly, especially with a good group of friends, then this would be your incentive. Certainly that was my incentive when I was younger. All my friends have long since moved on though, and the older I get the more other things become more important than wargaming.
Painting can be an incentive, but only if you like that aspect of the hobby. I'd rather watch other people paint myself. I was never any good or very interested in painting.