When it comes down to popular racing titles produced by Nintendo in relation to the past decade there is no question that Mario Kart Wii along with Mario Kart 8 stands out more than almost anything. Ever since, Mario Kart Wii was released for the Nintendo Wii back in 2008 the game managed to sell over 37 million copies worldwide and is considered to be the best selling title within the Mario Kart series in general. Despite, being the best selling Mario Kart in entire series some would argue that MK Wii not exactly the most popular entry the Nintendo has ever made. For the most part Mario Kart Wii sold more than Mario Kart 8 mainly because the Nintendo Wii was far more successful than the Wii-U.
Despite, not sell as much as Mario Kart Wii its a fact that Mario Kart 8 was the best selling game for the Wii-U reaching over 8.4 million units worldwide in sales. In fact, the Nintendo Switch version of the game Mario Kart 8: Deluxe is one of the most popular video games for that console right now. In fact, Mario Kart 8: Deluxe has managed to read over 10 million units worldwide in sales since its release back in April 2017. So in terms of which games is more popular overall Mario Kart 8 would definitely have the edge over Mario Kart Wii as far as popularity in relation to this past decade is concerned.