I mean, the writing was on the wall. Even before the election, he was saying things like: "Oh, they're gonna rig the election against me, folks", and his rhetoric was so toxic that at Republican debates, the moderators were asking him things like: "If you lose the election, will you abide by the peaceful transfer of power?" Which, of course, he didn't agree to.
I mean, yes, he hadn't actually incited people to try to overthrow the government at that point, but he very much was on record saying that that was his intention.