You're simply thinking of Linemans, Linebackers, Fullbacks and Quarterbacks.... Most WR, RB, CB, and Safeties tend to have quick feet, great pace, and are in the 5'8-6'0 range. Their bodies are conditioned for football but they are supreme athletes. These guys don't train to fit in the mold of soccer players but could, just like a lot of the more athletic soccer players train for soccer not to build athletic skills for American football. A lot of these athletes if soccer were chosen could potentially end up as great players.
For Basketball, again, you are thinking about a small portion of players who play the sport. Most who play the sport aren't even close to 6'5 and don't make it pro, but are extremely athletic. Across the country their are college basketball programs with a lack of height, and guys over 6'5. However they are filled with quick, coordinated players under 6'5, with the guards being largely under 6'2 down to the 5'8 range. I'm not saying it's a great chance these guys make great soccer players, but their is definitely a drain of talent potential.
Additionally, no, the difference in compensation between soccer and american football isn't even close. A two year career in the NFL at the minimum will far exceed what the average MLS player makes over the course of career. The floor is higher, and the ceiling is much higher. The minimum yearly salary is 64,500 in the MLS, you make that in NY, LA, Chicago, and that's not a great salary at all. The minimum in the NFL is 465,000. Average players in the MLS have to play years to make what comparably skilled players in American football make. Their isn't more advertising potential either. Only the top of the top make any kind of endorsement money that is sizable in US soccer.
You seem to just be talking about stuff you don't understand or know much about at all. I would advise to just give it up because I can refute almost anything I've seen you post. I don't attempt to try to diagnose the issues in the English youth system or wherever you are from because I wasn't raised their, and I don't know the ins and outs like you would. I think you should consider doing the same when it comes to discussing American soccer. You're woefully ignorant.
No, lower income kids do not play much at all. In the inner cities, the two sports are basketball and football. Basketball courts are all over cities for kids to play pick up games in, participate in recreational leagues, or just go an practice whenever they like. Football has a much bigger following and you find a lot of older men in cities trying to be role models for kids and keep them off the street, doing a lot to just get them to go to practice. People look at it as a way out, be it just for a scholarship or professional.
For soccer, that kind of thing doesn't exist. Parents have to usually drive kids decent distances to practices, even further to games. It's set up up in a way that does not facilitate impoverished people to play. If you are the child of a single parent, and they work multiple jobs... Then you are likely eliminated from playing soccer because it places such a burden on the parents in driving to and from practice and games. Their aren't fields in cities, and if their is, most of them are not open to the public.
This is America, this isn't Brazil, Nigeria, or Yugoslavia. The culture is completely different and the structure around the sport is completely different. The peope playing and attracted to the sport are completely different. It will take a very unique system to create an effective youth system here due to schooling, and the NCAA being essentially used as player development also.
Again, I'd advise you to just stop talking about things you clearly know nothing about. It's a bit tiring to read.
Excuse after excuse, it would be quicker to say " we just can't cut it " instead of trying to peddle a load of different excuses.