I don't know that the prior situation was sustainable and would have lasted much longer anyway. Using China for manufacturing is like using Amazon for sales. You are required to give them everything they need to take your business away.
So why the broad spectrum tariffs? Why are we blowing up our trade relationships with Canada, the EU, UK, Mexico, Taiwan, Japan, Australia, New Zealand, South Korea and many many other countries who have been good, honest trade partners?
This isn't about China's sins in economic dealings. If it was, the tariffs would only target China and there is an explicit case to be made that indeed, we should be putting tariffs on Chinese made goods, the same pattern may hold true for India as well FWIW.
But our other trading partners have been very good to the American economy, and we blew that up overnight.
We left a vacuum for another economic force to fill now. All the nations we put tariffs on, not only will the tariff US made goods, they're now overnight going to be looking for a place to transact hundreds of billions worth of units, and China can now offer sweetheart deals to absorb that trade, and that weakens the US (and as consequence, western) alliances.
If if comes to pass that the 21st century is a Chinese one, it will be this long con that launched the whole thing: "We'll manufacture anything you want real cheap, just show us how to do it."
The U.S. outsourcing it's manufacturing to China is likely to go down as one of the biggest economic and political self-owns of the modern era.
Now if they are pissed and totally lost trust then we are totally fucked. But if they are pissed and willing to negotiate then maybe something can be salvaged out of this. It would be nice to have 20th century hong kong esque zero duty free trade between the US, EU, Mercosur, Canada, and all the other friendly nations as a result of us all learning how dumb this is. But I won't hold my breath.