Almost everything is dependent on nostalgia today, on all forms of media. The reason for this is to maximize profit.
Bolded: You got this backwards, all of those franchises are actually better at changing up the formula than Nintendo, every main Metal Gear game has added something to formula, final fantasy always changes up the battle system and as for resident evil ( cof cof.. RE4, RE5 and last but not least RE7 all would like to have a word with you.)
And Nintendo is the most risk averse gaming company out there. Look at the Wii ¿Ever wonderer why it was basically a gamecube with motion controls? If they were about the risk, the Wii would've been an HD capable console, it is not because if it had flopped, they would had made some money out of it.
Same story with the WiiU, use the Wii brand to make it sell, didn't work and dropped it faster than a red hot ball of iron on their hands.
Also, look at how they manage their IPs, they are very creative, but also super conservative.