I can't imagine the foreign fanbase is going to show up at the WC or Olympics at the levels projected when either was awarded.
The last time that the WC was in the US (94), is still the highest total attendance despite the tournament expanding the number of games from 52 to 64. The per match average attendance is 25% higher than the next closest WC @69k per game vs 53k at next closest.
Until last year for the Paris Olympics, the record for Summer Olympics attendance was Atlanta in 1996.
The Trump crackdown on non-white people has to make the organizers of both the WC and the Olympics cringe in fear over attendance.