Since I am at work I will only respond to point 4 Western Devs.
The reason the sales has no impact on Nintendo consoles is because over the last 3 and a half generation Nintendo gamers have been deserting Nintendo for various reasons. It all slowly started with N64 and every generation more and more left so therefore sales of 3rd party games clearly will go down as only the pure loyalist Nintendo only gamers want only Nintendo games.
Ever generation it is become more and more hard to justify a Nintendo console when you get older and time limited and just can't be F'ed owning so many consoles.
If Nintendo were able to get full 3rd party Western support then after a couple gens you watch those sales would go up as the kids have not shifted to PS or XBOX. They would be playing and the next round of kids and their kids would be playing.