Cars and cellphones are fun to imagine here, but the reality is that China's manufacturing might has little to do with those industries. Every big box store in your city is filled with all kinds of random crap from napkin holders, BBQ grills, decorative Santa statues, and so on.
A toy manufacturer wanted to return their processes back to the US to avoid all of the liability of undetected chemical substitution. They found out there was no manufacturing capability in US for the fancy cardboard boxes which show off the toys but make them transportable. They sourced those from outside of the US and kept on their path. So one can argue that's a temporary problem... but it points to how serious of a factor time and speed of adaptability is here. It can't be done overnight.
Trade wars have real impacts before the market can catch up. A stupid but real example is like the UK where their Toberlone bars have been redesigned to decrease the chocolate content. A scary example is how the international oil trade shut down our domestic shale oil production and bankrupted dozens of companies very quickly.
This is the big leagues! Poor choices at the scale of the US economy have enormous impacts.