I will say it won't sell at the pace of the Wii. It might not even have a single 20 million+ year. But there is a chance that it's on the market for longer than the Wii was and might stay relevant for longer, which could result in it crawling past the Wii. Or I could be completely misjudging it and it ends up selling like crazy, blasts right past the 100 million mark and reaches 120+ mill or so.

Wii Launched at 249$ and went to 199$ not long after if my memory servers me right?
Then it had a Wii Mini that was 99$.  It also had the advantage of playing gamecube games.

And everyone was super hyped to try motion controlls for the first time.
There was like a wave or movement amoung the casuals... that wanted to try a console (for motion controlls), even if they wherent gamers.

I dont think the Switch has "that", if it outsells the Wii, it wont be because it has motion controlls.

Those "casual" gamers are on mobilephones these days imo.

Not in the same time span. If Nintendo manages to keep up the monentum long enough it will.

So far so good. They still have a lot of levers to operate: smash release, pokemon release, online service launch, price-cuts, 2D mario, mario movie, potential hardware revisions or add-ons.
Time will tell.

Nintendo would have to fuck up pretty badly for it not to, honestly.

Mainline Pokemon, hardware revisions, multiple purchases per household, and a longer lifespan should push it passed the Wii.

Nope, it got a price cut to $199 in Sept 2009, nearly 3 years after launch.

Initially my guess was 80-85m but I can see 100m being plausible due to the fact its a unified userbase, Vita users coming on board, likely to have a longer life on the market, no portable competition and the fact that right now they're selling it like a console which down the line I can see change in approach when they cut the price and begin selling it like a portable to fully migrate the 3DS and Vita userbases over.

It would be late late into the platform's life should it pass Wii though and likely in the phasing out period of the platform's life.

Too soon to tell.

Sure, but then again I'm looking at the Switch's sales potential as being something closer to Nintendo handhelds rather than Nintendo consoles. The Switch may not have the casual appeal the Wii had but it has four things that I can think of that the Wii didn't have: the full Japanese market, its positioning as a device that can have multiple units per household, full 1st party support from Nintendo and the Switch's non-dependence on finicky blue ocean markets (so far).

Easily. Unless Nintendo completely destroys it with terrible business decisions.

It will happen because the Switch will be the better console.

Initially, I predicted 80m lifetime before the Nintendo Switch Launched.
I revised that to 110m lifetime once we got more of a picture at 2017's E3.
I will revise that higher if the Third Party Nintendo Switch landscape improve notably, otherwise, I am sticking around 110m for my lifetime prediction for a bit longer.

Anyway, Nintendo Switch has a lot in its favor right now:
-It is already 15.7% of the way to Wii's lifetime sales
-Best first year of any console ever to build momentum off of
-Its getting Wii U, 3DS, Vita, and Lapsed Gamers
-Unreleased Games: Smash Bros., Pokemon, 2D Mario, Animal Crossing, Pikmin, Metroid, etc.
-Possible Price Cuts over the next 8 years: $249, $199, $149, $129, $99
-Possible Hardware Revisions: Switch Mini, Switch XL, Switch TV, Switch SP, Etc.
-Longer Console Cycle: 7 to 10 years
-Wild Card #1: ???Third Party support may greatly improve as the install base explodes around the pokemon phase???
-Wild Card #2: New breakout hit games (like Wii sports, Brain Age, Nintendogs, etc.)