It has never happened in the history of the world that a company or country could maintain its technological advance indefinitely.
Either China will catch up on this or that particular technology will become obsolete. But it is certain that they won't stay behind forever (measured in a small number of decades at most).
I mean you’ve definitely just had technology disappear though, usually because of war. Damascus Steel was a lost military tech. We could certainly end up just accidentally (or worse, intentionally) bomb this stuff out of existence so nobody has it.
This is kind of like saying you can prove everyone dies based on the evidence that everyone who is not currently alive has died.
You might place an upper limit using history but in this case I'd guess that limit would end up being much larger than the present semiconductor industry itself might last.
Right but if you dont say how long it will take them, youre not really saying anything.