That's a good point but I can't believe that every console doesn't have it's own unique set of keys so that if you compromise one before SW patches land, it won't be much use in the ecosystem.
It depends. I'm going to speak in general terms, since I obviously don't know how every single system works, but per-console keys are used for pairing system storage to the motherboard and maybe keeping save data from being copied from user to user. Most CDNs don't really provide the option for on-the-fly per user encryption, so instead you serve up games encrypted with title keys and then issue each console a title key that's encrypted with a per-console key. Disc games need to be encrypted with keys that every system already has, otherwise you can't actually use the disc to play the game.
As for the value of being able to do 'hero attacks' on game consoles, let me point out that once you have a cleartext dump of a game, you've already done most of the work. The Xbox 360 was actually very well secured, to the point where it was easier to hack a disc drive to inject fake authentication data into a normal DVD-R than to actually hack a 360's CPU to run copied games. That's why we didn't have widely-accessible homebrew on that platform for the longest time. Furthermore, you can make emulators that just don't care about authenticating media (because why would they) and run cleartext games on those.
