China believes that it will inevitably stop being the manufacturing hub of the world. More than that, they're actually planning for it. They give out billions in interest free loans to governments all over Africa with the purpose of building infrastructure which will hopefully assist the region in industralizing. This buys them favor with politicians who happily cut some off the top for themselves, and with the people of that country, who have new bridges and Dams. They believe that Africa will boom and become industrialized like southeast asia has, allowing them to be modernly productive yet archaicly cheap in terms of labour. It's also why they've been investing so heavily in building their "New Silk Road" trade network, like building a Naval Base in Djibouti.