When NYC put 7000 police officers on extra duty, put up barricades, but the Trumpsters failed to show up. The made for TV, staged fiasco of 100,000 snarling Trump fans crashing police barricades wasn't going to happen.
The optics of no one showing up for the event would be even worse.
Nah I think it was canceled because everybody realized it was another J6 fedop where they were attempting to foment fictitious charges against protestors -and- everyone figured out they rally had no case against Trump. (Please don't confuse this post for support for Trump).