Some people still play Wii, some people still play PSMove, and some Kinect, it does not mean it was not a fad.

The games you listed, here are the install stats.
Graviturn  - 100,000 - 500,000

Install stats for games that only use touchscreen. (android since ios dont list installs)
Line POP - 10,000,000 - 50,000,000
Line Pokopang - 10,000,000 - 50,000,000
Candy Crush Saga  - 100,000,000 - 500,000,000

Endless run racers: The only popular ones actually use swipe and not the accelerometer, Temple run 1 and 2, use swipe, the popularity of games that use tilt sensor are significantly lower than the games that dont, and this can be confirmed by simple searches and browsing the highest rated and highest installed games lists.

Accelerometers are included simply because removing them would prevent the few users that actually want to play this games, and from people that use the tilt sensor in other applications like health tracking and mapping, from doing so, and no mobile phone manufacturer is going to remove features having MORE features is the ammunition needed to compete in the mobile hardware market today.

Again, motion controls is a fad.

No, it's not. If it died out in 2009 you'd have point, but it didn't. Fads only last a couple of years. With VR becoming a thing again, (something that was also declared a "dead fad" years ago) motion has a potentially huge future ahead of it.

And yet, the reality is people will just end up using VR with standard game controllers.

The thing about VR is when it first emerged, it had neither the power or the resolution to be believable, and the unit price was sky high, as these technical limitations are lifted we get a resurgance, motion control has no major stumbling block stopping it from being successful, it just isnt successful anymore, because it was a fad  - people got excited for this new and exciting way of playing games, and a few years later were bored of it.

As for dying out in 2009, the only reason this particular fad lasted a few years longer is because i was tied to a games console, and the initial surge in popularity eventually encouraged other people to try it, prolonging the fad, while some were new to the console and motion controls, others were already done with it and, in the case of most kids, wee simply using it to get their bi-yearly fix of tv/movie spinoff games and Lego titles.

It's nice that you feel that motion control isnt a fad, but it simply was.

"Fads" all spread by people introducing it to others, it's how they become as such. Wii would have been doing 2012 numbers in 2010 if it were truly a fad. The hallmark of a fad is very brief lifespan.  Wii wasn't short-lived, it lasted the normal amount of time for a video game console. Nintendo's systems have pretty much always targeted a 5-6 year lifespan. Wii actually lasted longer than, say, GBA or N64.

Motion controls is the fad, the Wii was a games console, not "motion control", unless you are trying to argue that the Wii had nothing besides motion control to maintain sales.

I would just take it along with a few other things in that pile.

you seem to keep missing the point or just ignoring it. No one said anything about life cycles. They are talking HOW it sold in that time. It went from being on track to having a more than 50% market share to about 35%. Lets say its not a fad. Fine, but there is nothing normal about a consoel on track to sell more than PS2(some were even saying ti could sell 200mil) to not even able to match the PS1. That is odd no matter how one spins it.

That's not at all because Nintendo horribly mismanaged it's final years or anything.