It is not "the US" that imports Japanese or Chinese electrical appliances, but an individual from the US, or a group of Americans. They import these appliances because they believe that a profit can be made. And governments ought not interfere in these transactions.
MMT basically holds that governments have control of unlimited amounts of real wealth — thanks to money-printing power. But if this were really true, countries like the USSR and North Korea could simply create money until they became wealthy nations.
Social media giants enjoy a cocktail of government contracts, government favoritism, and government-granted monopoly power. As a result, it will be difficult for new startups to offer much competition.