They'll change if it's for the greater good. When I was an undergrad (1998-03), students would throw marshmallows at each other and sometimes on the field (the TV cameramen would film inside a little cage for protection). But then we switched to FieldTurf, and marshmallows that landed on the turf could potentially melt and stick there. Lloyd Carr urged the students to stop in a little message before the first game with the new surface, and just like that, it stopped.
Homefield advantage largely comes down to fan participation. The current students have to decide if they want to chant something that the other 80% of the stadium won't participate in, or something that everyone will.