"despite" playing the first three? Good topic title.
If that's what you meant to ask, it's because I think because it's one of gaming's greatest series, even though MGS2's story lost something in the translation.
If you mean "despite not playing" them, you miss something in the story, for sure. But the games are so popular because of the gameplay mechanics, so MGS4 will still be a blast even if the story is kind of weird and new to people. It's partly my favorite series because it gives the player so many substantive ways to customize how they play.
And it's true that many, many people played MGS1 and then MGS2 who didn't play the previous games. MG has always done a really good job of telling you what happened previously in the universe. You can understand everything through the characters' dialogue and reactions to things you, the player, maybe don't remember.
