Regarding 3DS sales, I think people are underestimating the fact that the pricing is still very bad compared to Nintendo's previous systems, it's not at a "mass market" level worldwide. Yes, there's the cheap 2DS, but the naming doesn't help with generating new sales, and advertising isn't very good outside Japan. They need to come off the "DS" name and start something different, and actually advertise better. The software is there though. Price it reasonably, with decent amount of software, and it'll take off.
As for the Home Console front, I personally don't see a "downward trend" in the sense that Nintendo is becoming irrelevant simply because they're Nintendo, it's more like Nintendo is screwing up each hardware launch more so than the last (aside from Wii) and making the same mistakes + greater ones at that. If Nintendo for once launched a home console with minimal issues, they would see decent numbers, that means no name issues, no lack of significant advertising, no failed gimmicks, no underpowered hardware relative to the rest of the industry, no more huge software droughts, at least SOME third party support etc, but that hasn't happened. Wii U is rock bottom, the successor won't do worse just because there's this supposed "trend", unless people believe they'll screw up that hardware worse than Wii U. They'll need to do that in order to sell less than Wii U, it won't happen " just because".









