There are some interesting conditions as to what the US had to do in order to host the world cup. This included the introduction of a professional football league, this of course would become the MLS which started a year before the world cup (the NASL folded in 84 and would only restart in 25 years later in 2009).
Lets say either Morrocco or Brazil win hosting rights to the event instead and both beat out the US in voting (which is another question alltogether but we'll say dodgy FIFA business gets it through much like Qatar IOTL).
What happens
a) To the sport in the US in the short term
b) what does US soccer look like today, both on a national team standpoint and domestically. Does a professional domestic league exist and if so, how big would the league be now?
c) How does this affect maybe foreign players and the prospects of players going to the states and leagues outside of europe (such as Beckham and more recently Dos Santos and Giovinco etc).
d) What about the national team, do players still have a strong domestic league or will they be forced to move to europe in the hope of actually playing professionally.
e) What would grass roots football be like, would participation rates be still very high.
f) Do the U.S. become disheartened or do they go after 98, 02, 06 and beyond?