Oh snap, time to get back! *pops neck*
I'm gonna combine everyone's comments into a giant gumbo pot, so dig through this if you're interested in picking a subject.
If Nintendo is going to become another Sega, then that means all the trappings of the Saturn would have to be repeated by the Wii U. Yant scratched the surface of the Saturns problems, but it goes a little deeper. For example, the gigantic launch failure. A "surprise" early release, exclusive retailers, and no third party support for four months (at least Nintendo has some). People talk about Sony's PS2 being the Sega killer, but the first PlayStation wiped the floor with the Saturn. However, not because of technology, but because of (quite frankly) retarded business strategy.
Then we got to the Dreamcast, a really neat console, but at this point Sega was a three-legged horse. Any advantage gained by their competitors would be disastrous. Well, I think we have this covered: the emergence of DVDs. In a way, the death of Sega was the result of a DVD player, not a gaming console. If anything else, there was also piracy due to, as previously stated, how ridiculously easy the process was to play CD copies.
Now, most everything else said has been mainly opinion, if not a little oracle forecasting. I don't have much right to override those types of things, but I have my own as well.
I still stick to the "your expectations" route. Again, I constantly see a trend online where older gamers seem to expect Nintendo to "grow up" with them. In essence, that Nintendo should conform to a select age group's interests and alter their franchises to such interests. Adding blood, getting more violent, exploring sex, and so forth. That's where Sony and Microsoft come in, but Nintendo doesn't need to do such frivolous things.
We've grown up, and while I wouldn't call Nintendo themselves "kiddy," they're the gaming company that's there for the younger audience. Now, Sony and Microsoft do have kid oriented games, but it's not where they excel. Mario & Co. reign supreme with children. While we had the NES or SNES, the newer generations have Wii/Wii U. You might cry out, "Oh woe is they for they know not of the 8-bit!" True, but Mario is Mario. I once volunteered at an elementary school about two years ago, and there I was the "old kid" that watched over the playground. I got to hear some conversations, most I've left to be forgotten to oblivion, except for one.
"Dude, have you played Super Mario Galaxy?" Immediately after the question, an onslaught of excitement filled the conversation. I've played Super Mario Galaxy, it's a great game. To these kids though, it was like a nirvana their television emitted into their young minds. So yeah, they've probably never played Super Mario Bros., Super Mario World, Super Mario RPG, Super Mario 64, and probably Super Mario Sunshine, but Mario is Mario. I began with Super Mario Land 2: 6 Golden Coins, and now there are those who may start out with Super Mario Galaxy.
Tradition vs. Innovation. That's what I hoped would be talked about a bit more, especially if we were to talk about Nintendo games. In a sense, Nintendo games fuse those two qualities of gaming into one. You could say Mario is still collecting coins, and other items, but where is collecting them? The Zelda "formula" rarely changes, but where are we and what's the story? Kirby still absorbs enemies, but what new powers has he developed?
I've already explain the audience issue, but there's still something that needs to be clear: the "casual" audience has always existed. The NES was also a really popular Nintendo console, never forget that. To this day, you'll still have older folk calling video game consoles "Nintendos," though now we get the occasionally "Xbox." There were non-gamers who wanted to see the hub-bub about the "Nintendo Entertainment System." In fact, one of my neighbors was a child who's family did exactly that. She is in no way a gamer, but she has had her NES, Super Mario Bros., Punch-Out, and Kirby's Adventure with her for many years. With the Wii, Nintendo simply began the process of harnessing the potential consumer base.
I don't consider the Wii a fad. Truthfully, a video game console can't really be a "fad." It can have excitement surrounding it's name, popularity, and overall enjoyment. That's all in the consumers' mindset, but fads are primarily a concept, something that's hip because "it's hip." A video game console can actually be fun by being played, not be an item that sits around and is "cool." (i.e. Beanie Babies, Furbies, and especially Pet Rock) The casual market can fun with their Wiis, but it's not the same as a gamer's enjoyment.
For example, another neighbor of mine has a Nintendo Wii, but seriously, she has two games for it. Still, it's "fun" for her. Of course, she and her friends want to come over and play Mario Kart. Thanks Mario, you bring the girls to the yard.
This leads to the real point I want to make: the Wii U. Nintendo can still retain a casual market with the console, and in reality, that's why we have a Wii U. Market retention, and etc. Still, as I've said before, there are signs that Nintendo is beginning to put more focus into the core market that has been slipping away. The ability to have an external HDD seems to speak, "If you want a few games, flash memory; for everything else, connect your large hard drive!" I can't say much else as anything else would be speculation, but about Apple...
The 3DS... it feels so out of place. The Nintendo DS was such a great equalizer with the entire Nintendo market. Grandson and grandma could very well have their own Nintendo DS, but the 3DS... Apple could begin their gaming push by filling in the gap. I wanted to address this however because I don't honestly believe Apple could take Nintendo's casual market because the Wii U will be the home console whereas Apple can only (for now) compete as a handheld. Even an iPad couldn't compete with the Wii U.
Sorry for the little tangent at the end, but I've never really had to think about Apple dominating Nintendo. It's a little ludicrous, especially with the lack of focus on gaming on Apple's part.