Sports experts?

I was wondering,Why do they have to have 6 points for a touchdown and one point for a field goal,with a total of seven points for football,and in basketball 2 points for a basket and 3 for one thats farther away,when in hockey things are 1 point,why can't everything be counted as one point.I was just wondering.I don't watch alot of sports but it just seems to be alot easier