The issue isn’t how full the place was. The issue is how full a place, by comparison, Joe Biden can draw.
–Joe can never have such a rally, for the same reason Hillary couldn’t: No one is really all that wild about him. Even here - considering how anti-Trump many posters are - support for Joe is very tepid.
–Terry McAuliffe has said Joe’s strategy is to essentially not leave his house, let alone say much (apparently to avoid his gaffes and looking like the doddering old man he is). Having just watched Trump on TV, his energy is like 1000% more than Joe Biden. Further, FWIW, Joe’s strategy is exactly the same as Thomas Dewey in 1948, and we saw how that worked for Tom (against a very beatable president, too, who Dewey always outpolled, often by large margins, except on election day).
–COVID is a dodge for Joe - he (or at least his handlers) knows how poorly he speaks and how old he looks, so “Team Joe” will assiduously avoid rallies, including by blaming covid for why these can’t be held.
So the “phone booth” cracks might be enjoyable to your side, but they really impress no one.