Let's take this apart for a moment.
1. Exploit for 7.x: Nobody has a working exploit for 7.x in ARM9. Even if ssspwn works, it is limited to userland, meaning not ARM9. Not even gateway has updated their support for 7.x exploit, which would surely create a great deal more sales for them if they did, so we can conclude not even gateway has an exploit for 7.x.
2. Pre-calculated NCCH keys: The firmware sets 2 keys, X and Y. The Y is dependent on the app being launched, the X is set at firmware boot. You cannot dump X because even if said exploit for 7.x exists, it would not be exploitable at boot time. So no point in discussing this further.
3. Bootrom: Not something a homebrew person can dump as it is unreadable from within the system. But well in the possibilities of gateway by throwing enough money at it and using million dollar equipment.
So, with these 3 points analysed, do tell how at this point in time, some homebrew hacker will decrypt those 7.x mset and eshop CXI ?
Hint: they can't
Easy with a hardware RAM dumper you can dump the new arm11 code for those apps