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.
In every situation like this there are people who know it's just a party and people who take everything very seriously, it's amusing unto itself but a significant majority of Trump's popularity came from autistic memelords on 4chan, you'll notice way less pepe frogs and pede references in pro trump communities ever since the party has been over