It's not just that they've won 3/4 generations, but that they're also the top selling systems of all time.

1. PS2
2. PS1
3. Wii
4. PS3

If PS4 doesn't do well, XB1 will do worse, for sure. And WiiU will not be a competitor, PS4 taps into a huge market, one WiiU can't sell too.

I doubt PS3 is going to get any more major exclusives but it's still getting multi platform games. It might take another 4 years but I think it could pass the Wii.

I don't see any scenario where the PS4 could lose this gen. Microsoft's inability to compete in Japan will keep them in second place, and the WiiU isn't going anywhere.  

Sony was only with PS1 and PS2 the real winner. You can't speak of a winner or of a clear market leader when all are almost even with their shares. You clearly can speak about a market leader when one console sold 160 millions and the others are around 20 millions like it was with the PS2. But you can't speak about a market leader when all are around 100 millions at the end like it was this generation. And it will be probabl the same this generation no real market leader when sony sold at the end 100 millions ps4 and Microsft 90millions xbones , to minor difference that this woudl have any impact or any kind of advantage for one of the companies.

its a tough call, but i dont think it will do
it will be close though, since Wii is going to be dead by Jan 2015
i dont expect very long legs for PS3. it was a good run though
it may hit 100m but wont pass Wii

And what people too have to consider is that only the unattached hardware sales reveal nothing about the market leader. It is more a combination of the overall software sales, plus the profit a platform generates( xbox live, ps+ fees; digital sales; win loss ratio of Hardware ;software and so on) and the hardware sales of the platform combined which defines a market leader.
Take Apple and Samsung as example, Samsung actually sales way way more Smartphones than Apple when you just look at the unattached sales but Apple still make a lot more money with iphone than Samsung does, no one doubts that Apple is the market leader even if Samsung actually sells more phones.

No, they won two generations and Nintendo won three as it stands today. You can't ignore consoles before Sony, unless you're a fan boy. But they have sold more home consoles overall, which is impressive given that Nintendo was around longer.

ony consoles are long seller, so you should wait 2-3 years, PS3 will surely be the winner of the last generation.

The Wii was a phenomenal case.. Utter domination one half of a generation, and then an utter failure the 2nd half