It's utterly crazy that anyone outside Nvidia knows any of this, much less all of it. Has there been a years long public reverse engineering effort that I didn't hear about until now?

Yes, there actually was a years long public reverse engineering effort; since 2023 there were some academic papers, solving parts of it. It has sped up a lot recently, probably due to accumulated knowledge, and due to AI use.

If you think about it, the effort is economically incentivized.

Buy a shitton of these things, spend a year working on the unlock. If you find one, sell the shitton at 5x higher price (which is what happened).