I think people are conditioned to expect games with an "exploitative" ad-based or in-app purchase model. The conditioning to not expect an upfront cost to purchase is reinforced by the huge number of low/no effort apps resulting from the low barrier to entry. People don't want to pay for apps with little or no utility, lots of bugs, etc., and that's the vast majority of apps.

It's going to take a big player having the fortitude sustain the marketing (and potential losses) to sell an app that doesn't fit in this paradigm.