The US can regulate monopolies, it just doesn't want to.

When the Sherman Antitrust Act was originally passed in the 1890s, the American judicial system systematically refused to apply it to business trusts. They didn't strike them down as unconstitutional, of course - they just argued that, oh no, poor old Congress doesn't know what words mean, they really meant to ban labor unions and not the monopolistic businesses they were trying to combat. This continued through several decades and multiple follow-up bills explicitly prohibiting courts from doing this (they did it anyway).

For a few decades this practice stopped; mostly because the monopolists drove the world economy off the Marianas trench and there was a social democrat in the White House willing to do unspeakably authoritarian shit to the courts[0]. Also, WWII happened.

This, however, was just a diversion from the mean. In 1980s a bunch of federal judges decided to pull a similar stunt, reinterpreting antitrust law not as a prohibition against economic concentration but merely one against raising prices. The resulting "consumer welfare" standard wound up getting adopted by the executive branch[1] and since then we don't regulate monopolies at all.

Because here's the thing: monopolies don't raise prices. They lower them.[2]

The east has worse monopoly problems than we currently do. China doesn't have a solution to monopoly, it is the monopoly. Every major Chinese corporation is extremely exploitative of their workers, and has major ties to the government and Chinese Communist Party. Chinese law has a broken welfare system, no internal freedom of movement, and bans labor unions. South Korea is democratically run[3] but the chaebols are so large that they form their own voting blocs. 11% of the country's labor force is employed by Samsung. Japan had similar problems - after Matthew Perry forced open their borders, they saw America's monopolists and, not wanting to be eaten by them, formed their own. The zaibatsu reigned until the end of WWII, where America, having now forced Japan's unconditional surrender at the threat of nuclear annihilation, used their position as Japan's occupiers to hack the companies in question up into little pieces.

The solution to monopoly is to destroy the monopoly. No more and no less. It's not a problem of not understanding the new technology. The problem is that monopolists tend to be several steps ahead of you; deposing them requires sustained focus and an economically enfranchised democracy. In the case of the Internet, many very well-meaning and intelligent hacker types were pushing for keeping the Internet unregulated, because they were worried about social conservatives censoring us in the name of the moral panic of the day, or the RIAA censoring us in the name of music still being a saleable commodity. This was co-opted by the monopolists to carve out vast swaths of the Internet for themselves.

The EU didn't make this same mistake and actually enforced their antitrust laws on US tech companies. Problem is, they could only really fine Google, not break them up, so for a good decade tech enthusiasts had this idea in their heads that this was just a revenue generating exercise for the EU. The amount of consumer good-will Google and Apple had (and still has), especially in the tech space, was (and is) downright obscene.

[0] If that wasn't bad enough for the monopolists, there were a bunch of capital-f Fascists trying to seize power as well. The monopolists considered front-running the Fascists and having Smedley Butler assassinate FDR and crown himself dictator, but fortunately for us he had a change of heart and defected.

[1] Thanks, Reagan.

[2] When a large portion of goods are made by a handful of companies, those companies have significant negotiating leverage and economies of scale. Competitive free markets are actually more inefficient because you're paying a redundancy and freedom premium.

[3] Only after 1987. South Korea used to be run by a military dictatorship.