I stayed about 160 nights in China this year.
It's getting harder to get a complimentary suite upgrade, and lounges are also more and more crowded.
Still, I don't think it's the number of platinum or higher elites. Rather, people are simply booking suites and executive rooms since the delta of rates for suite/executive rooms and regular rooms is often insignificant in China.
Case in point: Chengdu Marriott, Dec. 12-13
Regular room (41 Sq m) 970 CNY
Executive Suite (70 Sq m) 1450 CNY
The delta is only 480 CNY or $65.
No wonder I didn't get an upgrade the last time I stayed there. Hotel manager told me all suites are full.