In theory, if there's a truely competitive market (has such a thijg evwr actually existed for anything?) it shouldn't matter what a particular store charges as any other store could come in and charge a lower percentage and provide a 'better' service.
That can't happen without very open access to alternative app stores though.
In an idealized enviornment whoever could provide the best app store for the least amount of overhead and fees would be successful.
That said there's something about defaults and the many year headstart Apple has had with their own app store which makes me skeptical that even in a completely open environment that there could ever realistically be a mass alternative for everyone and expecting the average user to care about developer fees they don't understand is a hard sell.