Why did Nintendo's legendary Shigeru Miyamoto make Pikmin? He wanted to appeal to high school girls, that's why.
When it comes to game design, there are a scant few people who can be trusted to weave pure gold almost every time, and Nintendo's Shigeru Miyamoto is on that very short list. The man has been noted for his ability to create the fantastic from the mundane: Much of Miyamoto's inspiration for games like Mario and Zelda came from his childhood exploring in the Japanese countryside; similarly, 2001's Pikmin came from his fondness for gardening.
Gardening may have been what inspired Pikmin, but what about the why? "Every once in a while, you want to make something that high school girls can get into," Miyamoto said at a recent symposium (where he also confirmed that Nintendo was developing new hardware). He wanted to make a game that said schoolgirls would be able to pick up and play - an obvious precursor of the "gaming should be accessible to everybody" philosophy that drove the development of the Wii.
Good to know, Mr. Miyamoto. I'm sure that there are plenty of gamers out there who would love to hear you elaborate on your thoughts on appealing to Japanese schoolgirls. Though I suspect your intentions might be a bit more wholesome.