While Stark Tower was the home base for the Avengers until it was replaced by the new facility in upstate New York, in the comics, one of the Avengers facilities is the old Stark family mansion on 5th Avenue in New York City.
Alternatively, we have to wonder if we’ll be getting the Avengers Mansion at some point during the next two Avengers movies.
It’s possible that if there’s a smaller team the decision was made to move to a smaller facility.
Could we see the Avengers, in whatever form they take in Infinity War working out of the mansion?