Let's talk about "plot", "story", and "play to find out."

[Thomas Shey]

That sounds like an argument for newer is better.

I'd say its more an argument for a clear--but true--tautology: newer is more popular, or in most cases it wouldn't be what was being sold. I know you hate arguments from popularity, but when it comes to finding players, that's all that matters in the end, like it or not.

 

[Thomas Shey]

The Market has, to a very large extent, said what it's been told to say.

While with D&D in particular because of its market-juggernaut status that could theoretically be true, it at least requires explaining why they would not be chasing the popular market rather than trying to make it; unlike some fields there's no self evident reason for them to do so. So if your claim is they swerved away from the popular rathet than toward it, I think its your obligation to at least present a credible reason they'd do that.

 

[Thomas Shey]

So when people select an RPG to play they are not making an informed choice, but are tricked by social pressure and marketing? Is marketing that powerful?

I'd say it largely depends on what "that powerful" means. There's a perennial argument about D&D's popularity, and how much of it is because of personal preference, and how much of it is because of its visibility and the network factors involved. Its an argument that never gets resolved because its an almost impossible question to test for in either direction.