Speaking as a man who has lived in Japan and worked for a Japanese company for nearly ten years, I am dubious just how pivotal Yamauchi was in all of this. The Japanese power structure commands an almost Godlike respect for company presidents and CEOs, regardless of their business acumen or decision-making ability. The company lives and dies by the whims of the president, and those same people are often given to making bad, often seemingly-random decisions. Certainly it was a bold move for Yamauchi to restructure Nintendo as a video game company but it probably didn't take a genius to see that playing cards, even at that time, weren't going to be big money makers for much longer.
I'd venture that, yeah, a lot of good ideas probably saw the light of day because of Yamauchi's go-ahead, but there are probably dozens, maybe hundreds of really great ideas that died in the board room because Yamauchi, for whatever reason, personally disliked it.
It's strange to me that a person who hated video games would be so revered by the gaming community. We're talking about a guy that, by the way, also never graduated college and inherited his company through no effort of his own.
Japanese companies are all the same. The president takes the credit for all the good ideas and decisions, but no doubt about it there is always some peon near the bottom actually coming up with those ideas and struggling to convince the president it's the right move. The idea that Yamauchi was some genius just because somebody else managed to convince him that video games would be big some day is ridiculous.