"China’s Population Could Shrink to Half by 2100"
"China’s population began shrinking in 2022, and the latest United Nations report indicates that it could slip to 1.3 billion in 2050 and then plummet to only 770 million in 2100."
https://www.scientificamerican.com/article/chinas-population-could-shrink-to-half-by-2100/Estimates for U.S. population have more uncertainty, ranging from slightly fewer to slightly more Americans by then. Over time, China will see greater demographic pressures than the U.S. And China has greater respect for the elderly, but no social program to assist them with living expenses. That will create strains.
I think real estate investment isn't entirely the Chinese government's fault. In China, buying land is a traditional form of investment. I believe parents are traditionally supposed to buy a home/apartment for their children who are getting married. The desire to invest heavily in real estate was already there, and then stimulus added fuel to it. And now overbuilding has become a problem, with property developers paying for current real estate projects from the money coming in for later projects. That pyramid scheme caught up with them, leaving many people owning unfinished housing. I don't think that has entirely been resolved, in which case it remains a drag on the economy.
I doubt most young people understand the implications of TSMC shutting down. Good bye, new cell phones. Data centers can't get replacement parts, so response times have to degrade. In the pandemic, new car production stopped in the U.S., for lack of chips (which had been redirected to laptops, after car companies canceled their orders). Imagine no chips for anything, since so much of those come from TSMC. I think young people will notice when they can't buy a new phone, and their existing service gets slower or stops. But probably not until then.
If China and the U.S. go to war, both will lose. China has overprepared to defend itself, and could succeed at that. But they can't take over the U.S., so it would become a protracted war. Maybe people in China would tolerate it and be patriotic as the war unfolded... but once it ends, and their economy collapses... I think they'll get the same thing they did around WWII. A new government, by force.
Still, China has ordered its military to be prepared to invade Taiwan by 2027. But they also fired various military leaders around that time, suggesting they have a lot of work to do.