The Wii sports drop is huge. Also I think Kinect sports on the xbox 360 ( 6.06 million sales ) to Kinect sports rivals on the Xbox one ( 0.40 million sales ) saw a significant drop of around 93%.

Isn't Wii Sports Club digital only? and free for 24hrs of play at that?

Plus its a re-release of a game that has 80m copies out there, why would someone buy it again?

Bit of an odd one to compare imo.

Wii Fit and Brain Training on the other hand are better to analyse, especially the latter as it shows a obvious affect of mobile gaming on dedicated handhelds.

Zelda Phantom Hourglass to Spirit Tracks ia another big drop. PH was part of the 'Touch series' and I think its obvious it didn't appeal to the Brain Age crowd, hence the big drop off of ST.

Not really, Tropical freeze sold atleast over 1 million, unfortunate because its such an amazing game

Let's look at USA NPD data for a second. Ignore Chartz.

According to NPD data, Donkey Kong Country Returns hit nearly 3 million only a few years after being on the USA market.

Meanwhile, Donkey Kong Country: Tropical Freeze still hasn't hit 500,000.

It's abundantly clear that Donkey Kong Country: Tropical Freeze is a failure to NCL.

Tropical Freeze had a good deal greater production costs than the original with a more robust dev team...and for what? To sell 1/6th of its predecessor in the USA?

Well thats only In the USA. and also Wii had a bigger install base, it doesnt matter if it even sold only 100 K, its the best game of the gen so far for me, and idc about the sales. I just said it was unfortunate, also returns has 9 million something, and Tropical freeze has 1 million, Thats not so bad compared to the install base at 2014 february. EDIT: Returns actually only has 6 millions, so tropical freeze sold 5 million less. thats not a big drop at all compared to the install base, TBH tropical freeze sold preatty good compared that no one seems to mention it anymore when they talk about good Wii U games

I want to know what world you live in where a title that sells only 1/6th of its predecessor is "not a big drop at all," haha.

So what if the installbase was smaller? It's still a failure. Especially because it didn't move any Wii U consoles.

You have to keep in mind that Wii's active installbase back in 2010 was a lot smaller than its total installbase. Remember all of the soccer moms / grannies that bought it for Wii Fit and Wii Sports and nothing else? Yeah...you have to take that into consideration.

And, if you look at sales data Tropical Freeze has pretty much flatlined...so it's never even going to go anywhere above its current state.

Donkey Kong Country Returns continued to sell for years. But Tropical Freeze? It had a small run to cater to the Nintendo diehards and then promptly withered away.

And I don't think Donkey Kong Country: Tropical Freeze has even HIT one million yet. Chartz says it has, but I think Chartz is over-estimating here.

Dragon Quest IX > X (not exactly comparable but fun metintionning) : 5.77 > 1.23m 78% drop
FF tactics advance > FFTA2 :2.13 > 0.73m 65%

Percentage wise or pure sales?
I will say Tempest 2000 to Tempest 3000
2000 on the Jag was one of the top selling games on the machine,  but i'd be surprised if 3000 sold more than 2500 copies on the Nuon.

LittleBigPlanet: 5.77 million
LittleBigPlanet 3: 1 million

Idk what you are trying to prove here, its still an excellent game, i dont need a game to be a multi million seller, aslong as retro studios to keep delivering great games like this im happy. Also 1/6th is relative, Like the drop from Wii Sports to wii sports club is much more then 5 million, so compared to that it didnt drop much, 5 million is a big drop, but compared to the big install base and the marketing that went into Returns and not much into tropical freeze its still impressive of the low userbase of Wii U could make tropical freeze sell 1 million. That means it sold more then a zelda spin-off title, and yes ik hyrule warriors released like a couple of months later, but still DOnkey Kong isnt a huge franchise anymore. So i see 1 million copies sold of Tropical freeze preatty good