I think you are missing the point. The media was treating Marbury like shyt in new york knicks days, making him look like a scapegoat, to the point where he was like fukk it. He had the vision, vision to re-establish his brand, he didn't want to be that ring chasing bench warmer in nba, he still wanted to play and make big money, so he went to china which obviously had a big market, and he re-established his image and found the fanbase that treated him good.
True, no one in america cares about chinese league, but the point is that no matter what marbury did else in the nba league for the last 6 years it would have been irrelevant to nba fans and they would have still treated him like a joke just like new york media made him look like.
He made business moves, why not go to the pretty big market and be the first american chinese basketball legend and build a huge fanbase and make more money instead of spending the rest of your career playing as a bench warmer for nba teams and keep hearing the media talk shyt about his underwhelming career? And it's a good move because if this league keeps getting more popular his brand will be as well because he is the first big brand foreign player out there, they treat him almost as good as MJ in the NBA.