Re: they have become fairly good at producing cars for the domestic market by now.
Worried no doubt like the Americans too. But the worry is about competition around the world.
What you like to call artificial barriers (a silly word and wrongly spelled) is about trade agreements.
Nobody is forced to buy a single Chinese car, but as countries like to also export to China they will have an agreement on what can be exported and imported, hopefully not using a "Truss" for that.
I had one of the very first Toyotas in Europe, a Toyota Corona 1966 1,5L.
https://en.wikipedia.org/wiki/Toyota_Corona#Third_generation_(T40,_T50;_1964)
It served me well and was totally problem free, unexciting, (the next was an Alfa Romeo 1750 with every possible problem, but exciting).
The big joke then was - Lars when will you get a real Yota.
I saw the Toyota more than 20 years later in the traffic, still looking sound.
Anyway, will the Chinese manage the same, who knows, but they will try, but regardless we still produce cars in Europe too.
And the number one and two in the world are Toyota and VW.