This is a common police and prosecutorial mindset and tactic. The ridicule what they call "the SODI defense," meaning Some Other Dude Did It. But really, there are only two defenses to an accusation of a crime: 1) There was no crime, and 2) I didn't commit the crime. If the defendant didn't commit the crime, then "some other dude" did. So, the majority of defendants employ the SODI defense, and prosecutors don't like it. Eats into their winning record, and besides, so they think, most defendants are scumbags anyway, so if they didn't do this one, the did plenty of others.
I suppose the prosecutors would ask, "if Trump didn't do it, who did?" The answer is obvious: The rioters did the riot. They have been punished far out of proportion for their crimes, but they did it. If anyone else is to blame, I'd look to the FBI plants, that the FBI still refuses to say were not there, or what they were doing if they were. I'd blame them before I blame the guy who told the demonstrators to go peacefully to the Capitol and protest.
We see how unfair it is to try to deprive the defendant of his most obvious defense when it is a famous person like Trump. But it happens every day in every country. Police, prosecutors, and their puppets on Grand Juries bring people to trial. By the time the trial jury sees the case, it has been packages like a Hollywood production, and the defendant stands little chance.
Unless - like Donald Trump - they have the resources to fight back.