The revolution goes well beyond sales, here's a few main points:
1. The dawn of fitness gaming. Wii Fit, EA Active, etc have sold millions of copies, overshadowing major gaming staples like the recent offerings from Grand Theft Auto series. Physical therapists, gyms, etc are putting Wii systems in their businesses for the fitness games and motor skill games like Wii Sports. This is a previously uncharted ground for the game industry.
2. Motion controls. The Wii brought about a rebirth of motion control gaming to the industry. How developers have used it is irrelevant, but those who incorporated it well have been paid hansomely for their efforts. Furthermore, the Wii "fad" of motion controls has forced the hand of its competitors to make their own ventures into motion controls for 2010.
3. Putting the familiy back together through gaming. Since the days of Atari 2600, gaming had slowy become more of a "one machine, one person" system, especially seen in force by the birth of the Sony PlayStation. More solitary game design, then the incorporation of online gaming, all made gaming a very solitary, if not obsessive, activity. The Wii has brought the family together, focusing on games that the whole family can learn easily, catering to "party gaming" and so forth.
4. Gameplay, not graphics. The industry as a whole had been growing a bloodlust for prettier graphics, but the same rehashed product underneath. With the Wii's graphical limitations, developers spent more time focusing on the game itself, and less concentration on the graphics. This has changed the way developers think and approach their game design, for the Wii and beyond it.
I'd say it's been quite a revolution from the industry we knew in the times before the Wii.
I agree wholeheartedly with points 1 & 2, and I somewhat agree with point #4, but only in that this gen has shown that graphics don't really matter, and not that gameplay is suddenly more important than it was before. Other than that, I believe you're overstating Nintendo's actions this gen somewhat.
The ps3/360 were definitely pushing the graphics as much as possible, but there are countless titles on the two systems that provide new gaming experiences, and aren't just rehased titles with a new coat of paint. There was nothing quite like Assassin's Creed on the market when it released, Gears of War made the cover system a staple of modern shooters, LittleBigPlanet brings numerous new ideas to the table, Demon's Souls is the most unique RPG in years, and don't even get me started on all the quirky and different PSN/XBL tiles out there, like Flower, the Pixeljunk games, Geometry Wars, Braid, etc. The Wii didn't inspire these developers to provide great gameplay in their titles. Any decent developer knows gameplay is a vital part of any game.
All the Wii has done is show that graphics aren't a vital part of the equation, as you can get by solely on great gameplay. But then, numerous PSN/XBL titles have done this as well.
And honestly, outside of the Wii Sports series and its numerous clones, please show me the great strides in gameplay developers have made as a result of the Wii. Was it Super Mario Galaxy, that plays eerily similar to Super Mario 64? Was it Super Smash Bros. Brawl, that is best played with a GameCube controller? Was it new Super Mario Bros. Wii, that is played like any other 2D Mario? Was it Punch Out, which plays identical to the original? Was it Monster Hunter 3, which is sold bundled with the Classic Controller? Was it the numerous shooters on Wii, that do their best to mimic PC or arcade controls? Sports games and racers are really the only genres I've seen that have truly benefited from the Wii Remote thus far (though I'm sure Zelda Wii will shake up the action genre in ways games like No More Heroes could only dream of).
As for point #3, social gaming has always been Nintendo's forte. They have pushed four player multiplayer games for three gens now, with franchises like Mario Kart, Super Smash Bros., and Mario Party. This gen is no different. It's just that with the success of the Wii due to the popularity of the Wii Remote, they have a better position from which to market the social gaming scene. This wasn't a revolution. These ideas have been around (and quite popular, looking at the sales of past Nintendo titles) for years now. And the other consoles aren't devoid of good offline multiplayer games. Halo built it's success partly because of four player offline coop and lan parties, and LittleBigPlanet is an amazing multiplayer game, one I enjoy with my nieces and nephew regularly.