Yes, but he's not going to lose anything over it. He's spent four years acting like that: anyone who could be alienated already has been. If it doesn't cost him, why should he stop?I'm a Trump supporter and am not jazzed here. Trump need not have been so rude. He should have been much more laid back, let Biden be Biden, and then calmly and confidently respond. Instead he bullied and interrupted. Very unnecessary.
I think this is partly Trump's personality, and that he doesn't have the right temperament for formal debate, it's a style that just doesn't suit him. He's a narcissistic showman who operates on instinct, not a thinker, planner and orator. I don't think he knows enough detail, he doesn't concentrate or care enough to prepare properly, and he has too strong a desire to belittle and dominate to allow a patient back-and-forth on the issues. As examples, some of his recent performances (the Town Hall and that Axios interview) more along these lines he did not come out of well at all.
But he knows he can disrupt the process and turn it into chaos so that Biden can't win, either. Trump's potential "win" here was to shake Biden into losing his cool - and he failed. Thus the only real losers were the debate format itself, the hapless host, and the USA generally for how it this unedifying spectacle presented its politics to a global audience.
It will be interesting to see if Trump changes tack for the next debate. Being so far behind in the polls, he can't settle for a "no result" like this one. If he can't break Biden's composure, he will need to come at him with the issues. I am not sure whether he'll manage it. Trump clearly can keep on-script: he has done it before, but he seems to lose his vim, become staid and mechanical, because it's not his natural mode. There's a sense he wants to break out and tubthump to a crowd, and I suspect in future debates when the contest flows, and especially if he feels he's not winning, there's a strong likelihood he'll degenerate it towards chaos again.