It is hard to comprehend (even for those of us who live here) how large & diverse the US is. You could divide it into 6-10 areas the size of the UK and ask the question about each and get different answers. And yes, social class is a factor in some of the sports, just not as strictly divided as you might have in the UK.

Texas and the south have LOTS of racing and football (lower to middle class, 'mostly'), certain smaller areas have more tennis and Polo..*grin*...soccer happens 'most' where there are large populations of kids whose families come from Europe, Latin America...etc..

but the 'big' (read:TV promoted) sports (basketball,baseball,football, and often, hockey) are common in every area, just a bit more so in major metropolitan areas.

Soccer has the serious disadvantage of playing continuously, so sponsors do not like it, even if there were not 3-4 competing sports wanting air time.