Mm, don't agree. You can earn a very handsome amount of money working for Tencent and Huawei.

I'd accept "undercutting", but that's a corporate/macro pricing trend, not a trend for salaries among embedded devs in China. I suspect many companies who are undercutting pricing are getting funded by the Chinese government. They're still paying people quite well, just because they need talented engineers just as much as their competitors do.