Because investors have done what their name implies. Invested. They've given money to a business (specifically Nintendo) in order to make more back later. It's like taking out a loan, only the loan tries to control you into doing what it thinks is the best way of making money to pay it back.
These same investors, that were trying to get Nintendo more mobile/casual focused were the ones calling for Iwata to step down as president. So screw them.
Yeah. My main hope is that the new CEO has some background in video games, so that they won't just turn Nintendo into a mobile cashcow kind of company (And while this definitely is a worst case scenario, I could see pressure from investors forcing a "business" minded CEO into doing it).
Whenever you can, you need to play that game. It is quite possibly one of the best games of the last generation, if not of all time. Just be warned, it is very, very long. My current play-through is at around 65 hours and i'm still not close to being finished yet.