Many manufacturing parts used by US companies are sourced in China. This is especially true for parts containing rare earth metals and the metals themselves for which China is practically the sole source. If the trade war becomes very difficult for the Chinese they could basically cut the amount of these items supplied to the US which would have a crippling effect on US high-tech and our military. We have foolishly ignored this problem for many years which could come back to bite us.
For how long? That situation is not really indicative of the overall $850B problem. It's like when then media zooms in on the one kid in crowd of military aged "refugees" and say whole families are emigrating. That is a misrepresentation of the situation.
But back to your example: the supply situation is fluid and not static. A new supply WILL come on line, domestic hopefully.