It's all about popularity.
Honestly, I don't think most people in China care or know the difference between Lang Lang and Yundi. Deutsche Grammophone is my favorite, simply because they released most of my favorite music played by my favorite artists or symphonies. They aimed the mainland China market when they signed Yundi, and was hopeful that base would support his international career. However, what I can't understand, probably Deutsche Grammophone couldn't either, is, why China doesn't promote a home-grown musician, who's far more superior in REAL music playing, but rather spending the resource to promote Lang Lang.
Imagine what would have happened if Li was given the role to play that few minutes at the Olympics.
Not saying Lang Lang is awful at playing, he's actually pretty good if you don't look at him. But I just can't stand his fake showman style.