I see both sides of it to be honest. Most "Let's Plays" are harmless. However games that rely on story can indeed have a Let's Play make a negative impact on sales revenue. Regardless, it IS free advertising and for those who stop doing Nintendo games there will be others happy to fork over the $ because people will still want to see them and they'll get more views because the high profile ones aren't doing it anymore.
:lol Far from it actually. The Wii U is doing poorly, yes (which is sad, EASILY the best console this generation thus far) but Amiibos are making a killing as is they're handheld platforms. Of the three big players Nintendo is actually doing the best. Sony, as a company, is in dire straights. PS4 is doing very well but it can't hold up that ship by itself. Microsoft has indicated that XB1 might be their last system, playing with selling the XB division off. The only one who's full steam ahead, and has LOADS of money in the bank is Nintendo. They easily have the best IP's in the business and their funds are such that they could take a big hit on the Wii U AND their next few consoles and still be in the game.
Nintendo makes a LOT of dumb calls. I agree that this is one of them. However the right calls they make have made them the most secure name in the biz.