When it was scheduled there was no issue. Trump hadn't decided to attack Iran at that time. By the time the attacks happened and Trump started banning Iranian officials, fans, coach, it was too late. The games had been announced and tickets were sold.
When Iranian team was forced to stay in Mexico there was a whole discussion on this on an online forum that I was reading and someone did the full timeline math and it would have meant refunding a lot of tickets, moving New Zealand to Mexico, moving another match from Mexico to US, refunding those tickets, etc. Plus fans travelling would need to change their plans last minute, so I think FIFA kept things as is.
Edited by Minionite - an hour ago