For the same reason that why you buy most of what you own instead of say, grow everything you eat, make your own clothes and live in log cabins from trees you chop down.
It's simply much more efficient to focus on doing one thing instead of trying to cover everything. This is true on a grander scale as well. If those countries try to do a lot of the things they aren't as efficient in ultimately they'll be worse off than if they just mostly focus on something they're more efficient at AND selling them to bidders that need it more.
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At the same time TradeSNS will crack down all kinds of illegal dissemination activities and harmful information, building a harmonious space.