This is also due to the structure of the leagues. In America (for the most part) if your team is last in the league (NFL) you get rewarded. This is not the case in Europe in fact the opposite, the team gets regulated to a lower league for getting last. That in itself
tells me that European football athletes are playing for their lives rather than playing for a guaranteed check.
I think for the most part, American sports (unless they are in the playoffs) are not very easy to bet on because of variables involved. With baseball, one wrong pitch could be a grand-slam rather than the end of the inning with 2 outs, with basketball missed shots, or wasting the clock at the end, and with American football we have fumbles, interceptions, and missed calls. I think the best sport is European football.