> "If this was the case, the Chinese government would have placed import restrictions on US chip manufacturers."

I do not know full details, but China did exactly that. There were articles about limiting Nvidia chip imports more than a year ago. It really highlighted the absurdity of the export ban.

To my non-expert knowledge, the reasoning behind the export ban has never been explained beyond a vague assertion that China would do some sort of evil with AI if they have bigger GPUs than some arbitrary number of transistors, and also some silliness where paying a 15% tax made some of the GPUs safe to export. It has been pretty great for Huawei.