Except expanded audience gamers bought plenty of crap for years (Carnival Games, mini-game collections galore).
They don't care about "quality" in the way you think.
Nintendo Land is a pretty damn high quality game, so is Wii Fit U (better than Wii Fit or Wii Fit Plus), so is Wii Party U (far better than Wii Party) relative to the genres they are in. Even Kinect Sports on XBox One is quite high quality.
This audience just doesn't care anymore, they continue to buy crap, they just do so today on the iOS/Android marketplace where junk like Kim Kardashian's game can become a big hit.
If Nintendo wants to make games for casuals, they certainly can. It just means selling superficial software and chasing trends and then selling it for $1 a pop.
They're not willing to do that, as such they are irrelevant today to the casual gamer.
This is an audience base that thinks Flappy Bird is "awesome!". If anything Nintendo tried waaaaay too hard with Nintendo Land, they missed the point, that audience doesn't want anything even that complicated or deep, Nintendo Land needed to be dumbed down far more than what it was actually to appeal to this audience. Casual gamers are the reality TV fans of the game business or the pop music fans of the music industry.
Not to anywhere near as much numbers as a game such as Wii Sports. Heck its not like Nintendoland didn't sell, but it didn't sell anywhere like a Wii sports did. Nintendo doesn't have anything at the moment to equal another Wii Sports or Wii fit (Wii U versions won't cut it)
Wrong they care about quality, their definition of it is different than what the hardcore thinks is quality, they are looking for the value in fun, some minigame collections do give value to them, but to a far lesser degree than a game such as Wii Sports or Wii Fit did.
No, these are largely games that are well built, but they lack the same fun that those who bought Wii Sports and Wii Fit on the original Wii value, it lacks the quality they desire.
Those games give value to them for free or $1, its not like they'll spend $60 on those games, they will on a game that achieves the value they found in Wii Sports and Wii Fit, but for a mobile time waster they'll shell out maybe a dollar or two.
No if they want to make games for the expanded audience, they'll have to find a way to give the expanded audience the same sort of value they gave when the Wii Fit and Wii Sports were released.