ATP tennis will never have a broad base representation of U.S. players and hence will never be a broadly followed sport in the USA. Basketball, football, baseball and even soccer development is supported by communities and schools. These athletes are sponsored school systems, continuing through colleges. Tennis players need to pay for court time in the winter. Tennis is also a skill sport which requires countless hours with an instructor which cost betweeen $75-120 per hour in the northeast. Entering local USTA tournamnet cost $65, which rises every other year. Now if your good enough to be highly ranked in your section, you can qualify for Nationals which cost oodles of $$$ for travel flights, hotel rooms and restaurants and additional $75 -100 entry fees. Only middle class or wealthy families can support a gifted player from the ages of 6 to 18 through the monetary demands of professional tennis development. The ascent of the Williams sistas into the pro game is an anomaly. In the U.S., professional player will typically come from the well to do. I don't see anything that the USTA will nor can do to broaden the sport.