Because the opportunity to get Trump was gone, his body now under a pile of agents. Snipers gave Crooks plenty of opportunity before then. Setup, pre-planned, Biden's (puppeteer's) fault.
Someone around here posted a close-up blowup pic of Trump and his detail, and they focused on the lapel pins of those personal detail ‘agents’.
They stated it resembled the US Marshal pin, not SS..
I don’t have a familiarity with either pin, but if Trump’s closest personal detail are wearing US Marshal pins, that’s a tell that SS may be extremely compromised..