This is similar to the manned Chinese manned space program. First they bought Soyuz from Russia. Then they made major changes, although the spacecraft remained similar. Now they have the glory of their own program.
Some things, a nation does for propaganda, just because it wants to be a leader. If China offered NBA players more than they make here or in Europe, almost all players would jump. With lower attendance and TV ratings, the NBA would financially fold and the remaining players would jump to China, since the alternative would be D-League type money. (The D-League would have already financially folded before the NBA had, anyway.)
Why would China do all this only temporarily, until the new contract got worked out? It would be permanent. If they went to all the trouble, they would want something lasting.
This would create a strain in the Republican Party. Some would thunder patriotically, "Who lost the NBA?" and want subsidies here to keep them. Others would hew to the small government theory that they selectively use to cut only quality of life services.
China might steal our other sports, too. Good thought experiment, Rasta. But now for some reality about the next 30 years.
As we go more and more into debt to China, money can't flow in just one direction. To keep a semblance of balance of trade, China will increasingly buy up America--businesses and land. Eventually they'll get to sports leagues, but that is low priority compared to brain draining technological employees, which the US will protect to the end. When China gets to them, you'll know it's all over. I give it 20 years till everyone knows it's all dying, then another 20-30 years of futile struggle.
People will look back at this thread and say, We were joking but it came true!