Graphics have been "good enough" for the majority of consumers for a long time. The PS2 blew the XBox and the GameCube out of the water, and both those systems had much better graphics. Any PS2/XB multiplat looked better on the XB, and any PS2/GC multiplat looked better on the GC. The butt-ugly graphics never hurt the Grand Theft Auto games.

So I agree. Photorealism is only cutting-edge for a month anyway.

I would only expect that sequels would improve graphically on the Wii.
The thing is, I find that these Wii titles are so radically different that you can never pinpoint one game which beats another in almost every way.

As for "HD" games, it seems that graphics are going back downwards (Splinter Cell's graphics seem 2007). I guess that is due to the peak of the 360's graphical power coming so early (Gears of War 2)

In terms of Wii games being evergreen, that is due possibly a wider appeal (depending on the title) the brand name (Wii, Mario) effective ads, and proper price drops (not because the game flopped, but because no one feels comfortable paying $50 for House of the Dead.)

Non-evergreen titles sell because of hype. These are the titles like Halo that sell 3-4 million in their first week and then slide off the charts. Those first week sales actually represent about 4-5 months of pre-orders, driven by screenshots, trailers, and previews.

How can you know the quality of the game even before it's release? For people that want graphics that answer is easy. For people that actually care about gameplay, controls, accessibility, etc... they have to wait for the game to come out and actually play it before they can decide to purchase it.

Hence evergreen titles may not have the biggest "first-week" sales, but they have legs that span years and years as positive word-of mouth spreads.

So yes, the Wii's lack of focus on high-powered graphics to me is a main reason for the evergreen titles. Most of Nintendo's games are pleasant to look at, but don't have to have the latest cutting-edge graphics anyways. People that play their games are more interested in the diverse and enticing gameplay and motion controls that you really can't get on any other console right now.

I don't think graphical limitations have much to do with it at all...especially given that so few developers don't even bother looking at the Wii's limit, never mind trying to get to it.

The "evergreen" titles that you are talking about sell for such long periods of time because they have a wide appeal, and good word of mouth between communities of Wii gamers, but they were not hyped before release.
Pre-launch hype sells a hell of a lot of games to the "hardcore" crowd, I would say selling a lot to people who might have passed the game on if they had more time to think (ie feedback from actual gamers that play it, rather than reviewers) I know I would have bought Super Smash Bros. Brawl had it launched here in Europe nearer to the American release, instead with a couple of months to think it through I decided against it. This wasn't really due to negative feedback from gamers as I didn't hear much negative about it apart from the terrible online, but more that I decided it didn't really appeal to me.

Well, no other console has sold so much much so quickly as the Wii, and with Nintendo tapping a new market that could are less about graphics, they are going to buy the best games on the system, the Nintendo games. And from what I have seen from third parties, the second game of the series never do as well.
I will bet anyone Just Dance 2 don't reach the level of the first one.

It's very simple really... Wii and DS are targeted primarily at the "casual audience"... the casual audience doesn't troll video game websites on a daily basis or argue about graphics and which system is better... they simply buy what everyone else buys, which is why the same titles in the Wii's library are at the top of the heap, week after week and year after year.

This is the same reason why movies like the latest Twilight or Harry Potter films, and other hits like "The Dark Knight", and "Avatar" have such long legs at the box office.. because after all of the fanboys and movie geeks see it opening weekend, all of the casuals follow suit due to word of mouth and wanting to be a part of the latest fad or trend. Same concept with the Wii, and to a lesser extent the DS.

The "casual" audience is really what we should call the "mainstream" audience. I hate the word "casual" because it makes these people sound stupid and gullible as if they only really buy games like lemmings falling off a cliff. It's far from the truth. These are really the most cautious customers that are less influenced by hype and more influenced by actual playing time and recommendations from friends and family.

BTW, many people who buy the core games are casual gamers. Just that the gaming elitists stupidly think they all like those games for the same reason. Like thinking people buy FPS because of detailed graphics more than local multiplayer.

Nintendo is a bit less obvious though. For example in Super Mario 64 you don't bang her at the end, you "eat her cake".

Oh and Gran Turismo is not a video game either, it's for people who want to drive sports car but are too poor to afford them

Indeed.  The term casual itself was only created by the quote 'hardcore' reviewers and internet forum hoppers as stated above in order to distinguish the other side from the 'hardcore' gamer.  Its just like those who call anything that is 'family oriented' or not focused solely on the adult audience as being 'kiddy'.  Just because something is popular and sells well to people beyond 14-26 year old males, doesn't make it 'casual'.  You certainly wouldn't call a Pixar movie casual.  Or even better, an iphone.

As such, many Wii and DS games get labeled with that kiddy/casual rating.  But its mostly just coming from that same 'hardcore' camp as negative propaganda for anything that isn't solely targeting them.