Self-sufficiency should be the goal. If we can produce for our own needs, if producers prefer the domestic market rather than the export market, perhaps a nation can sufficiently stand on its own feet. Maybe we can be the least affected of all these trade wars.
But is politics that simple? Suppose if you are heavily dependent on the US from economic to military, now you don't want to depend on them anymore by becoming self-sufficient. Do you think the US will support and let you do it easily without trying to stop or sabotage? As you can see, any country that intends to reduce its dependence on them or wants to become independent will certainly be subject to sanctions ranging from economic to military and possibly causing that economy to collapse.
The most basic knowledge to maintain the throne, there is no better way than to force others to depend and obey you, or be willing to restrain their development. Because once they can grow, not only will they no longer depend on you, but they will even threaten your throne.
Not to mention, to be self-sufficient, we also need mineral resources, human resources, technology...How many countries have all of these factors? Self-sufficiency is something that every country thinks about but the problem is that it is easier said than done.