Quite simply because the main part of the market are the so called bro's. These people can't tell a good game from a bad and are easily influenced by the media. Sony and microsoft (and western third parties) know this and spend obscene ammounts of money to reach these people and make them think their latest game is the coolest and will allow them braging rights in their friend circle.
Nintendo ignores that segment and doesnt spend crazy ammounts of money on advertisement, wich in turn makes their popularity with said segment lower. Nintendo sells less systems, gains bad rep in the internet but makes a profit.







