China was never a part of this classic SE countries for backpackers.
If you wanna travel SE Asia, you go to Vietnam, Cambodia, Thailand etc..... but not to China.
It's too expensive when you travel on a low budget plus the most SE countries are visa free for many travellers or you can get a VOA easily but China.
US/Canadians can get a 10 years visa, Europeans can't.
And the costs for a tourist visa incl. all these service fees increased the last years and it's not cheap anymore.
In spite of my post upthread, I still like China on the whole.
That having been said, I am returning to the USA because the overall quality of living is better.
With respect to backpackers teaching English, this not common anymore. Sure you can get private gigs in apartments, but working at an actual school requires an RP.