So most of the new-game money publishers get is made in the first couple months, and most of the used-game money resellers get is made after that first couple months. They both make tidy profits off sales, since the market windows are fairly mutually exclusive.
You assume this is the natural order of things, and not a result of the way the marketplace works right now, but more to the point, this doesn’t prove anything, or tell us anything that isn’t already obvoious. Of course the revenue made from a game is going to decline after the period immediately following its release, and of course used game sales are going to increase as people finish the games and trade them in. Whether or not the game is being sold new at full retail price is immaterial here — even at a fraction of the original price, publishers still make money on game sales (at least until the retailer isn’t just clearing out stock).
There are other less scientific points to make that support my position (although they don't lend specifically to the process I just outlined): for instance, who's getting all pissy over used sales? And who's implementing online passes and DRM? Is it the developer, or the publisher? Do the devs even see a dime of new-game-sales money after two months? Probably not. Bonuses are likely already paid (although I can't speak with any certainty on this matter), because money. So now what does that leave you with? It leaves you with multiple giant, evil, faceless corporations fighting over profits from the secondhand market that devs wouldn't see a dime of. Now stop de facto defending EA, Ubisoft, and Activision for being money-grubbing assholes playing off people's sense of loyalty and wake up to the fact that used game sales are a good alternative to investing a good sum of money into something you may not even like (GameStop allows 1 week for a full refund on all used games, no questions asked, so if you don't like it you can literally just bring it back, unlike new games, where they'll only exchange it for another copy).
The thing is that most developers don’t bankroll their games out of pocket — the development is paid for by the publisher. Publishers may take a bunch of the long-tail revenue, but they’re not middlemen in the same way retailers are. If publishers don’t make enough money on a game to justify the resources put into it (and funding the development of a game is no small expense or risk), they’re not going to fund more, and they’re going to get more and more risk averse. Stuff like digital distribution and crowd funding is starting to change the funding model, but only a little bit.
Treating both publishers and retailers as evil middlemen fighting over profits at the expense of developers is a false equivalency, or at least a gross oversimplification.
Also, I’m not buying the null hypothesis framing: the fact is that none of us have granular enough raw data, or the time to sit down and do a thorough statistical analysis of it. You say you have data that you went out of your way not to link to, but unless it’s of a kind I’m not familiar with (i.e. not just earnings calls and NPD data), it’s not enough to prove anything. To me, in this kind of debate, the “null” hypothesis should be the obvious conclusion, which is that when money made from a game sale goes entirely to a retailer, it’s worse for the developer.