No discussion of baseball as team sport vs. individual sport would be complete without this clip of Al Capone’s speech on the subject from “The Untouchables.” For those who haven’t seen it, it’s pretty violent.
For the OP, most of the good reasons have already been mentioned. I think soccer isn’t popular here because:
It’s terrible on television. Either the field shrinks and all you see are little dots running around or it zooms in on two guys and you have no idea of the flow of the game.
There’s no scoring, and little in the way of easy stats to keep track of. Go look at World Cup scores from back in the day and you saw the occasional 5-3 match, even between good teams. Now, it’s usually 1-0, 1-1, or 0-0. The rest of the world looks at that and thinks it makes each score more meaningful. American’s don’t and are bored at the idea. At least in American football, when the offense screws up and can’t get a touchdown, they can at least try for a field goal. (Even then, if there are too many field goals, the rules will get changed to de-emphasize them.)
For baseball, even if there’s no scoring, there’s still plenty to keep track of and use to compare the performance of other players. I can go to baseball reference.com, and get oodles of stats for both batters and pitchers. I can show you, statistically, why Albert Belle got robbed of the MVP by Mo Vaughn. (Well, he got robbed by the BBWAA, but you get my point.) I can’t point out to you an easy set of stats for why Lionel Messi is so damned good. I can show you game tape, but it’s much more of a “feel” than a set of numbers.
For better or worse, soccer is looked on as very unmanly for all of the %@(#%! diving. We expect our athletic heroes to take a hard hit and keep on striving to their goal. Bo Jackson running over Brian Bosworth on Monday Night Football is what we want to see. Not some guy getting tapped on the side while running and collapsing like he’d been gut shot. (At least until after the ref decides whether or not to award a card/trainer runs out with spray can of magic juice. Then he pops right up like nothing happened.) Embellishing contact to make yourself look more like a victim and thereby gain competitive advantage, makes you look like a little bitch to the average American male. (Pretty much a direct quote from those average American guys I’ve tried to introduce to watching pro soccer.) I know, it’s “gamesmanship” or some other facet of the beautiful game that I just don’t understand. To make things worse, the culture forces guys to dive when they get fouled, otherwise the ref will swallow his whistle. For the most part, the average American male does not want his sports teams competing to see who can be the bigger victim. That flopping has entered the NBA has helped ruin that sport for me too.
Finally, do something about offsides already. Even hockey eventually modified the two-line pass rule. Make it like hockey with a “blue line” that the ball has to cross first, maybe double the length of the penalty box. But get rid of the judgment element and the seeming capriciousness of the rule. It will probably also increase scoring, which can’t be all bad.