@plawolf I believe they are doing so deliberately, and it is not as bad a strategy as you think.
Despite posturing and having a larger military right now, US knows it cannot compete with China’s larger economy and industry head on. They know this very well, because Imperial Japan tried it against them and failed in WW2.
Instead, they are trying to make a “walled garden” like you say, and try to hold out China or at least delay it for decades.
The Soviets showed that it was a valid strategy for resisting a long time and competing on even ground with economically and industrially more powerful rivals.
If America creates an iron curtain where US standards are the only way, they can keep fighting from that bubble. The Soviets had horrible consumer goods, but it didn’t slow them down because they enforced the Soviet standard and didn’t tolerate more advanced ones. In the same way, US not having 5G or very little electronics manufacturing potential once China cuts them off won’t hurt them if there is no better alternative domestically to compare to.