"But for some reason, I won't pay for something inside the Android store."
It could be one of several things, which would actually vary from person to person, but all leading to paltry returns for _most_ Android developers vs. iOS.
1) The "perceived value" proposition - To a user, Google is "the search engine" and Android "the mobile OS", but they're both free to use. In a consumer's mind, why wouldn't then _everything_ else, including the Marketplace apps, be free. It doesn't help matters that Rovio's runaway blockbuster cultural gamechanger shared timesink app Angry birds is free on Android (albeit with ads).
2) The blatant, flagrant, rampant, money-maker shaking heaps of copyright theft and IP violations that make it to the top of the Marketplace lists. It makes the whole thing feel like a grey market bazaar in old Morocco or Bangkok - just sketchy as all hell. How could I entrust my credit card with a service that allows GPL violators and copyright flouters to rise to the _very tippy top_ of the charts? I mean, alot of that has changed since Google started putting the screws on very obvious scofflaws like Nintendo emulator game ROM packs, Star Wars weapon simulators, and famous rapper soundboards. But the die may be cast for some of the old-school adopters.
3) The weird availability - Android phone users had to pirate Marketplace apps from day one if they didn't come from the US. Now they're expected to _pay_ for stuff? Sorry, but once you've told them it's free, it's free for a loooong time. Hell, Napster all taught us way back that music "wanted to be free". It's taken over a decade for paid music to come back into some semblance of making any money; coincidentally, it's via Apple's iTunes.