It's funny to see the level of fetishism around sushi. Here in Japan the spectrum goes all the way from cheap 100-yen-a-plate sushi joints, to Jiro. So it feels like sushi is a dish just like any other. In fact it always seemed to me like Kaiseki cuisine is probably a lot harder to prepare.
And the "wash rice for three years" thing is just a leftover from the way apprenticeship traditionally work here, whether it's for sushi or any other craft. It's always seemed to me like a particularly inefficient way of training someone and passing on your skills.