Trump has shown little interest in following rules or norms.
1. Trump's talked openly about a 3rd term.
2. In two successive elections Trump has not only refused to say he would abide by the voting results, but has both times, without evidence, claimed that there were large numbers of fraudulent, and asserted that he won big both times.
3. He's wanted these election results to go to the Supreme Court, where he hopes the fix is in.
4. Trump is reportedly looking into getting states with a GOP legislature in which the citizens voted for Biden to verify a Trump slate of electors instead
Trump is blatantly anti-democratic and just wants to win, regardless of legalities.
How could Trump stay in office if he lost the official vote?
Basically, he'd need military backing.
And if he used the Insurrection Act successfully once to crack heads in cities, he could invoke it again to protect his "win" against protesters, counting on support from an already compromised military.
It's not how things have played out yet. But it's not hard to see how this could have gone down and American democracy strangled. You don't wait until bad things happen until you prepare for them. The US dodged a bullet. But things could have gone differently and more fascist if the military indeed went into cities to quell/stomp on demonstrations. Which wasn't far from occurring.