They never embraced online gaming as they were scared of exposing kids to predators, vulgarity etc. and losing they family market that's been their bread and butter.
That cost them core gamers who are older, busier and can't have many gaming get togethers with friends for local MP. Those people moved onto Sony or MS where there are lots of online games with great online systems, easy chat, party chat etc where they can game with friends and use gaming as a way to stay in touch.
It is one of many things they must fix if they want to be relevant in the core gamer market for home consoles. They get away with it on 3ds as people care less about online mp etc in portables. But it's a huge deal on consoles.