The con was that the western companies gave over some serious IP for a decade or maybe 2 of cheap manufacturing. China was trying to industrialize for decades and essentially couldn’t do it. Walk in the western companies and they gave all the knowledge, skill, everything ($$$$) for some cheap labour ($).
Western companies think 5 years is a long term plan, so they’ll take whatever terms for 5 years (mayyybe 10 if they are unheard of long term planning) and after that is ???, but profit-now-is-everything-by-definition. But China is playing decades at a time, they are getting decades, close to a century of IP, for next to nothing in the big picture.