I wouldn't call Wii highly dominant, and neither was SNES. Every product will have its market leader and that lead will commonly be quite substantial. Look at iPhone initially, and now Samsung Galaxy there is no good reason for either of these phones to sell so much more than the rest, but they do because the market perceives them as best.

Looking at market share I think highly dominant must mean >50% market share on a minimum 3 console race. The consoles that qualify for highly dominant are PS and PS2. NES was also highly dominant but as it only had one competitor having >50% market share doesn't count, but as it sold 5:1 against Master System it definitely qualifies.

Another qualification for highly dominant is that the console should be the best seller in every market iun which it is sold.

All the other generations had a dominant console of course, but not highly dominant. So your question is rendered moot by the fact that not every generation has a highly dominant console.

I'm seeing ~20 Million based on the VGchartz numbers.  

29 Million vs 49 Million.

Do you have different numbers?

I used more of the criteria that a lead of over 10 million or so would be considered highly dominant. But I think now that everyone's criteria of using the percentage marketshare is better.

I'll say just dominant and that's really the question.

You're right. Genesis was 29 mil, I wrote it wrong as 39 which might have caused some confusion.

I've corrected it now.

That's just typical market behaviour. For any given product there will be a market leader and for many products the market leader is ahead by a long way. And this is irrespective of product quality. The better question is why do products, and services, in general tend to have a significant market leader when if you look objectively at things there isn't enough of a difference to really explain the level of dominance. Of course marketing and being the first cab off the rank usually helps a lot.

The interesting thing with consoles is that each generation is an unknown quantity especially when disruptive technology is introduced (CD and DVD with PS and PS2, waggle with Wii. So dominance from one product cycle to the next is less assured with consoles than with many other products. Which is the interesting thing.

I don't know what your definition of "overwhelmingly better" is but Gen 4, 7 and 8 don't really fit in mine.
The thread pretty much contradicts itself with its numbers,

Oh the numbers were in the OP.  Now i feel really silly.  I was looking them up myself seperatly.

The only gen I wouldn't consider overwhelming is the Wii generation, and specifically because of the reasons i mentioned above.

The Wii caught peoples imaginations, but the big multiplayer games were either on PS3 or 360.   Hence why they stuck around, and why multiconsole ownership was particularly high last generation.

Had Nintendo had better online... it might of been a whole different story.

Wii wasn't as dominant as ps1, ps2 and nes. It won but a lot of wii buyers bought it because it was a fad. A good reason why those wii users didn't purchase wiiu.

To all the people saying the wii wasn't dominant I disagree.... Nintendo stop supporting the wii the last year or two it was on the market and still outsold the ps3 and xbox 360 by 20,000,000 ...I honestly believe if nintendo wanted to support the wii  in its final two years it could have had sold close or more than the ps2 ...just my opinion ....nintendo doesn't care about if they sell the most ..they only care about making their consoles profitable....I have not once heard Nintendo brag that they had the biggest 1-2 punch in video game history (wii and ds) over 250,000,000 consoles sold more than ps3 , psp and xbox360 combined ...just saying 

This isn't meant to be an attack so pleas don't take it as one. I'm confused but why is it when we're having a console discussion some Nintendo fans bring up 3ds? It's a handheld. The handheld market is different from the console market. In theory a handheld should sell more than a console. Aren't there handheld threads?