I gotta say, I'm still not following. The model has been out there for years already. We know what to expect because it's already there and we have mountains of data to look at. None of your assumptions or fears have played out. So I'm confused. People who want to share their ideas for free can, and are, doing that. I haven't heard one person who thought, "I would normally give this away, but now I'm gonna charge for it." It's usually the opposite. With the introduction of Pay what you want, I've seen a lot MORE free products.
I have a hard time seeing where the seller is benefiting at the cost of the consumer. Presumably it's a win win, like any other product or service in existence. No one is forcing customers to spend money, last time I checked. You're also making the biggest flaw I hear in arguments like this (usually in the context of music sharing). That is, things should be free because it's all about sharing. That is fundamentally flawed because creating products is not free. You basically want something for free and me to foot the bill because "sharing is good for the community." Gotta call bullocks to that. I don't create things to make money (because there isn't much to be made in this hobby), but I do like to recoup as much of the costs as I can. Even if I completely discount the hundreds of hours of what my time is worth to create something, there are still a lot of other costs. I just released my superdungeon Felk Mor yesterday. The art commissions alone were over $1500. That's not counting costs for things like Adobe CS, editing, etc.
Basically, we have about a decade's worth of data to evaluate using this model. All evidence seems to point to your worries being largely unfounded, yet you insist on keeping with these assumptions. Do you have any evidence based on this data that supports your claims? You seem to think that there was this big deluge of free stuff out there that will disappear now. Seeing as how OneBookShelf has been in operation for over a decade, I need some hard evidence that supports that claim, because everything else seems to point otherwise.