Oh, I don't think it's a bit of a straw man. I already invest in prep time (labor), my materials, gas to get there, how great is my incentive to invest money play at the store?
First off, if you have another place to play, of course there's little incentive.
I come from the school of thought that if the prep work isn't itself part of the fun, you're playing the wrong game to begin with, so I don't count that as a cost. And likewise, a person usually has to pay for transport to any entertainment that isn't at home, so if we are comparing costs, that one doesn't make gaming more expensive in general (though it may for any individual, depending on where they live).
But beyond that, I think we just have different scales of what counts as a significant cost. I've been willing to do huge amounts of prep work, drive 10 hours each way, pay for hotel, gas, and eating out several meals for a weekend of good gaming. Maybe I'm crazy, but a short hop in the car, lugging few books around and $5 for an evening seems to me like a pittance, unless you're a starving college student or similarly really strapped for cash.
But I've been that starving student, too, and out of work and strapped or cash - and if you're not getting play elsewhere, that $5 for an entire evening still sounds like the cheapest entertainment to be found this side of a novel borrowed from the library. I'm just not seeing how this is somehow a bad deal, compared to how much entertainments usually cost in this world.