He’s so good at this
By 
Our Brooklyn bourgeois working class whisperers notwithstanding, most people do not actually like racist assholes constantly yelling at them about what they’ve seen in their 10-hour-a-day Fox News binges, and this is reflected in all of the scientific polling about last night’s debate:
CBS News and YouGov have been tracking respondents in battleground states, and they were able to quickly contact some of those respondents and ask those who watched the Tuesday debate what they thought. Overall, 48 percent said Biden won the debate, while 41 percent said Trump won, and 10 percent said it was a tie. As CBS elections and survey director Anthony Salvanto pointed out on air, this was pretty close to the support for each candidate going in.
Kabir Khanna of the CBS News Election and Survey Unit also points out that 42 percent of debate watchers said they thought worse of Trump afterward, and 24 percent said they thought better of him. In contrast, 32 percent said they thought worse of Biden, while 38 percent thought better of him.
CNN and SSRS also conducted an instant poll of debate watchers, and they found a more lopsided margin in Biden’s favor. Sixty percent of their respondents thought Biden won, while 28 percent thought Trump won.
Then we have the focus groups. Republican pollster Frank Luntz convened a focus group of 16 purportedly undecided voters from swing states, and in general they had kinder things to say about Biden’s performance than Trump’s.
The Vox in-house poll has similar results.
As Prokop says, whether this will change the race is unknown, but Trump is losing — anything that doesn’t move the needle hurts him, and he doesn’t have many opportunities left to change the race. (Given how little of an impression his ranting about it left night made on the public, a Bill Barr October Surprise about Hunter Biden seems pretty unlikely to do it. The underlying media groundwork just hasn’t been laid to do another EMAILS!)
So personally I don’t care if they change the format — if Trump wants to act like this twice more, fine with me, and if fewer people watch because the debates are unwatchable also fine with me.