I'm not sure how it was way more popular, but sold less.
That was an amazing Generation, with PS3, 360 and Wii. Sony's console has managed to regain ground with the release of the PS3 Slim, after having had a somewhat difficult start. Wii had 4 phenomenal years and then declined and give way to PS3 at the end of the generation. But it should be considered that 360 literally conquered America and even beat Nintendo Wii in units sold in NA, 47M VS 45.5M. Indeed, the XBox 360 had become the most popular console in NA, while PS3 had almost reached Wii in units sold in Europe. In the End Wii won in the Global, but really had a deep decline after 2009 : respectively, Wii, PS3 and 360 sold in the Global 21,2M, 13M and 10,16M in 2009, while 17,3M, 13,9M and 13,25M in 2010, and 11,5M, 14,7M and 13,8M in 2011, and 5M, 12,15M and 10,67 in 2012. Hard to say which one was more popular : 360 was in NA, PS3 was beasting in the end in Europe, and Wii a Monster in 2007-2009, starting to go down in 2010.