I don't think that was ever true. I think they just said that because they weren't confident in its success. It's less embarrassing and easier to move on when a weird new thing fails than when a flagship product does.
Well, I would think that, but they actually did try to bring the GB Micro to the market after the launch of the DS. It ended up being a big flop I believe, but I think Nintendo did have some vague dreams of there being 3 lines.
Well, RTU does have a reputation of being an emotional douchbag, but he is right though. There was once a time where specs was all Nintendo ever boasted about. Not saying that they still need to get involved with the spec race though anymore, but some people do believe that Nintendo was never about the specs, but they certainly were.
He's partially right, but it's ignoring two key details: handhelds and Nintendo themselves. In handheld market, Nintendo has never striven to be a powerhouse from the very beginning. The Gameboy was out shined in almost every way by competition (including literally due to the lack of a backlit screen). As far as actually describing themselves as not caring about graphics, I know this dates back to at least the early 2000s as I explicitly remember Nintendo stating that they saw innovation and good games as being more important than graphics when they released the original DS since it was underpowered in comparison to the PSP. So while in the console world Nintendo's modern ideology didn't show up until the Wii, it was a part of the company for much longer than the launch of the system.
There were also some offhand comments he made that were misleading, such as suggesting the disk size of the Gamecube as being the reason 3rd parties left Nintendo during the GCN era (it was definitely a factor, but one of many), but that's beside the point I guess.