Almost every console jailbreak required the use of a specific game, going all the way back to the original Xbox. PS1 and 2 required a specific disc or swapping in a legit disc. Even the NES required a real game cart alongside your third party carts.

It turns out that opening locks is a hell of a lot easier when you have a key.

The first 3DS exploit required Cubic Ninja, a terrible game that sold poorly and was instantly $80+ once it was revealed.

Cubic Ninja was not the first. The earlier ones used DS mode as an exploit using a cheap DS flashcard. I'm not even sure that was the first, but it was the first big one.

Console hacking has been like that for a very long time. But usually after the first exploits are found and hackers can start playing with things, many more follow. Though Nintendo has been stripping down the OS every new console so there’s less interesting stuff to exploit outside of games.

I remember having to buy GTA Liberty City Stories to jailbreak the PSP. Then there was the infamous Cubic Ninja jailbreak which caused the game to become worth hundreds of dollars.

This gives visibility to a lot more unencrypted code, so just give it time. More bugs will be found quickly now that the code is inspectable.

Don't need to buy the game.

Make a JP Nintendo account and download the demo (not available globally) https://store-jp.nintendo.com/item/software/D70010000010547

I did not know that.

Can still get it by the way if you access the page on mobile or with a mobile useragent, desktop seems to have a basic check added to prevent install.