#4 Regaining lost momentum is going to be difficult
This is the hardest part of the entire issue. The United States has relied on its successes in the international game to drive up interest and bring in new fans to the sport. While the NFL, MLB, NBA, and NHL dominate U.S. headlines, soccer has been gaining traction over the last decade.
Attendance levels are steadily rising year after year and with larger stadiums being included such as CenturyLink Field in Seattle or the new Mercedes-Benz Stadium in Atlanta, the interest is there. Supporters clubs for international teams are also on the rise as larger cities are finding more people wanting to come out and enjoy Saturday and Sunday morning soccer.
The United States missing the World Cup for the first time since 1986 is going to be a major blow, but it won't be insurmountable. Those who are already entrenched in the game aren't going anywhere, but growth will be difficult in the coming months with no World Cup to look forward to. MLS will be relied on, as well as the second division NASL, in order to keep interest high.