Well simply put there is no reason to update.

It like a FIFA or a BASEBALL or a BAKETBALL game for me, I update very few years as the game play doesn't really change.

If a game was designed to provide you exercise then why upgrade when the original is still working?

I don't think people buy consoles because they are revolutionnary but because they have fun games. WS and WF were obviously considered extremely fun for many people. There is no reason for these people to not want more of these fun experiences just like the exact same people, the casual gamers, want more MK or AC to play.

I agree.  I grabbed Your Shape Fitness Evolved for the Kinect and it actually worked.  So, when better versions came along, I just said "Good for them".  Never felt the need to buy another.  It's not like the excercises from 2010 or whatever suddenly quit being effective.

Most casual gamers have no brand loyality. So...

- casual sport/fitness gamers who cared about graphics probably have moved on to Sports Champions and Kinect Sports a while ago

- casual sport/fitness gamers who don't care about graphics will stay with their Wii for some years. If they finally decide to upgrade, they have several options and 360+Kinect is much cheaper than a WiiU

So I guess AC NL, Tomodatchi 3DS and future MK games are doomed too then... Except they are not.

The thing a lot of Nintendo fans here don't get is that the Wii really was a fluke, it was the right product at the right time and is extremely difficult to reproduce, see the PS1 and PS2 > PS3. Nintendo had been in decline in console sales leading up to it, the fans weren't enough to keep it competitive. The casuals were the reason they went from 20m the console before to 100m with this one. The Wii hit at just the right time with technology and a gimmick that brought in people who didn't grow up with gaming. The thing is casuals by their name and nature are not going to be repeat customers. They bought it, got the big games, maybe a Mario title, a couple simple motion based games and then that was it they had their fix. Most of them probably haven't touched it in years, at least people I know, it's either in a closet or they sold it because they never used it. Hence the flood of Wii's on the secondary market. It's doubtful that they will reinvest more than the original Wii in price to get a new console and another 50 for the game.

Nintendo surely converted some of those casuals into more reliable customers but the Wii U is not the big motion based gaming console that the Wii was, at this point anybody that wants motion gaming will probably have gone with Kinect now anyway or will be getting the XB1 in a couple months considering it's coming out before Wii Fit U. Also the lack of advertising by Nintendo is amazing, I never see anything on TV at least in the States and I watch channels that advertise the competition all the time. Casuals aren't on here or other gaming sites and unless they walk into the gaming aisle of their store, will probably not even realize what's out there.

Time will tell. A good marketing campain could lift the games well, but I doubt they'll be able to push anything near their wii counterparts. And if Nintendo doesn't market the games at all, then they'll be dead on arrival.

Maybe it was a fluke or maybe WS and WF will remain some of if not the biggest ips in this market. If you are so sure that it's the former then give me some blatant proofs because here you are just assuming things.

People bought the Wii because it was revolutionary. It was indeed fun at the same time, but Wii Sports was totally different. The Wii Remote changed the way we play. Nintendo arent going to recreate that buzz with the Wii U Gamepad.

These games will sell relatively well, but to expect anything similar to how these games did on Wii at this point is offensive.

I don't expect them to sell as much for the exact same reasons you give, I agree with you mostly. But I certainly expect them to sell really well, at least more than 10 millions each and as a result to still be very significant system sellers.