I would cap market share around 50% for PS4. The competition is too strong for any higher.
with XB1 getting the majority of the remainder because of Marketing. 25 - 35%. The XB1 problems are significant but solvable.
Wii U 15% - 25. The Wii U's problem is poisonous.

The only reason I don't think the XB1 can surpass the PS4, is because the X360 was so strong for the same reason PS2 was so strong, multiplats.
XB1 can't count on multiplats anymore because even at parity they don't really act in either consoles favor. Xbox has a lot of work to do building up their exclusive library and they have the least experience with this of the 3 manufacturers. The only Franchise exclusive at Launch was Forza, between this Gears and Halo they have a bunch of new ips they bought.
Not only do these new ips not have any guarantee of success, which Sony has a ton of experiencing with (trying and failing new ips), until they buy out the whole franchise, the larger PS4 marketshare becomes the more likely they will lose their exclusives i.e have to pay more. (Mass Effect). Nobody wants to sell on the smaller install base unless they have to. In other words, Xbox will have to change how they do things.

As for the Wii U, they are fighting against themselves and a battle with relevance at the same time. Id elaborate but ultimately, the 3DS is looking like a more viable secondary then the Wii U is.

shouldn't you wait to see how big the japan drop is before saying this? and even if it passes, there's no guarantee it will remain like that after mario kart comes.

It will do 60% marketshare probably

Did Mario Kart put the Gamecube ahead of the PS2? Or the N64 ahead of the PS1? You can't seriously expect one game to have that much of an impact.

PS4 is supply constrained in the west. It's baseline isn't 125k, we don't know what it is until it's in plentiful supply. So even if the Japan baseline is 10k, PS4 is still going to outsell WiiU 100k a week. By the time MK comes out PS4 is going to be 1m+ ahead of WiiU, MK isn't going to push that many consoles. WiiU barely managed 1m over the holiday season.

are we in the late 90's/early 20's? was mario kart as big at the time? did N64/gc release first?

and I'm not saying mario kart is the sole thing will keep wii u. I'm saying that whatever lead ps4 manages to get (if it gets) should be taken back after mario kart 8 releases. what happens beyond is more uncertain future.

now you're thinking wii u will go back to 40k imedeately after dk releases? and what the wii u did or did not in the holidays doesn't affect MK's power.

ps4's baseline should also lower considerably.

Ok by that logic NSMBU should have catapulted the WiiU to massive success. I mean earlier games sold nearly 30 million on the Wii and DS, why didn't it have the same impact on the WiiU? What about Wii Fit U? The earlier games sold over 20m each, why isn't it saving the WiiU considering how successful the series was?

I could go on but I made my point. Just because a game had massive success on the Wii, does not translate to massive success on the WiiU. 

During the holidays, week of Super Mario 3D World, WiiU barely passed 100k. (http://www.vgchartz.com/weekly/41602/Global/)

Why you think DK of all games is going to give WiiU a permanant and decent boost is beyond me, there is nothing to suggest it will.

WiiU's baseline will go below 40k, back to where it was last year, sub 30k.

Why will PS4's baseline lower? There is nothing that suggests that either, it is supply constrained, it's going to go up not down.

You were also way off on Japan launch, you said 140k? Did 320k.

The problem with the WiiU is the WiiU itself, so no price cuts and games will propel it to reasonable levels. It's been on the market for 16 months now, 2 holidays, a price cut and various blockbusters, yet it's all amounted to very little growth.