The US did exactly the same thing to the UK back in the early 20th century. All developing economies do. Protecting "Intellectual Property Rights" are only relevant to a nation's economy when those rights have value in that economy.
Nations that are in the "developing" state are generally the destination of outsourced manufacturing from developed states. They are arbitraging their lower costs of labor, less developed regulatory environment ("light touch", "economic development zones") and lower standards for environmental and other protections.
China is starting to enforce IPR because it now has the developed capacity to create IP.
Perhaps you're referring to the 19th century? The U.S. didn't recognize foreign copyrights until 1891: https://en.wikipedia.org/wiki/International_Copyright_Act_of... But when it did happen the enforcement apparatus (rule of law) executed the protections quickly and efficiently, AFAIU.
The difference with China is that China does recognize foreign copyrights. Why does the difference matter? Because consistent recognition in China can't happen with a simple passage of a law--that law exists. Any promises they make can't be upheld as their entire administrative apparatus is intertwined with communist party politics, and deficiencies in the political machine are what make enforcement so costly. Excepting espionage and trade secrets, I've never seen any evidence of an official or even unofficial policy of looking the other way for IPR violations; what I have seen is plenty of evidence that the processes for enforcement are byzantine, regardless of whether you're a domestic or foreign owned company, and too slow to catch violators such that it remains profitable. Have you been to developing countries? The black and grey markets are huge. You can't suppress these by fiat; you can only replace them, organically, with legal alternatives. (Same as digital piracy in the U.S.) The leadership can move mountains but they can't move a million mole hills nearly as easily.
The situation can and likely will improve without any major legal or political reforms. What you need, if you wish to accelerate this, is to incentivize the monied interests in China. How to do that? Maybe tie their foreign IP protections, particularly patents[1], on their domestic enforcement of copyright? That way corporations have an independent, self-serving interest in regularizing and normalizing copyright enforcement up and down the value chain, such as by building out their own value chain to replace the black and grey markets. Foreign trademarks are readily enforced in China, within the limits of what the bureaucracy can achieve, precisely because domestic companies have an interest in enforcement of their own trademarks domestically. And I'd bet big money that many of Disney's problems have already been solved by multiplexes owned by corporate conglomerates, which help to displace pirate DVD shops. Omnibus trade deals aren't going to get that done, and there's ample proof of this because there have been many.
You can't address a situation without understanding why it's happening. You can't ascribe simple motivations to such complex systems.[2] Whether you're Xi Jinping, Donald Trump, Vladimir Putin, Fidel Castro, or Hugo Chávez, you can't simply decree that some complex reform happen; things are more likely to go sideways or backwards. (OTOH, if you control the media--and even if you don't--you can simply declare that it happened, and more often than not enough people will believe you, or at least be satisfied.)
[1] Because language and cultural barriers means they're unlikely to have major export markets in copyrightable materials any time soon.
[2] I mean, you can. People do all the time, obviously. Simple narratives are an easy sell. But political reforms built on simple narratives don't have great track records.
The US did exactly the same thing to the UK back in the early 20th century. All developing economies do. Protecting "Intellectual Property Rights" are only relevant to a nation's economy when those rights have value in that economy.
Nations that are in the "developing" state are generally the destination of outsourced manufacturing from developed states. They are arbitraging their lower costs of labor, less developed regulatory environment ("light touch", "economic development zones") and lower standards for environmental and other protections.
China is starting to enforce IPR because it now has the developed capacity to create IP.