[ZenGum]

Quite a while, I'll guess. It's steel-reinforced concrete anchored deeply into solid rock. Actually I think the rock itself will be the weak point. Looking at the rock I think it might be limestone - there is a lot of that in China, and it is what forms the beautiful karst landscapes that they're probably visiting to look at. You can also see eroded dimpling in post 3 pic 2, which is typical of limestone. Limestone is water soluble and mobile at the best of times, and positively dissolves when exposed to even weak acid. Look at the smog in that valley! Every drop of rain will trickle mild acid down the face of that cliff, seeping into cracks and gaps, until one day ...

Or perhaps the most obvious risk is a big block of the cliff above coming loose and chashing down on the path.

I'd walk it, from a safety point of view, but I'm not sure why, given that the lovely view is pretty much clouded by smog. Yech.