Mate, what I believe is that China is confident for some reasons against the US tariff war, which is that their greater part of economy depends largely on exports, right, and if the US imposes higher tariff rates on China, then mate, think about how many big companies that are built in China that are US-based, big example Apple factories, and some other big known brands. And imposing higher tariff rates on China will also mean that increased inflation rates in the US. What do you think? mate, this is just my point of view. CMIIW!
And your facts are also valid here, because these tariff wars will also affect the Chinese economy as well, as some days ago I was reading some news headlines that the Chinese economy is also collapsing badly. Maybe, this can be a reason that prompts both US and Chinese presidents to negotiate to get some good end points to settle this tariff war.
In war both sides will be hurt which means higher inflation (and generally worse economic conditions) in both countries and since this is a global war in other countries as well with varied degrees. We've already seen the inflation in US rise and millions of people protest against this war their president started!
As for China, those who are saying "it is collapsing" are the same people who were saying "Russian economy is collapsing in a month" over 3 years ago! That's just nonsense. Chinese economy will be hurt but it won't collapse. It would take a lot more than that to collapse it.
Additionally in my comment you quoted above from a year ago, I was talking about other countries that would join that war
against China. But Trump went ahead and made the stupidest mistake by waging an economic war against almost the entire world which meant other countries that might have joined in US campaign not only didn't join that side, but instead they joined the Chinese side.
We even saw something nobody would have believed when Japan and South Korea got closer to China!!! Even Europe is getting closer to China and overall US is being isolated...