Hot tubs require outdoor space.  Most of Chinese people live in apartments and either have very small or no balcony.  And if you are rich enough to own a single house, you normally have very tall buildings within site of your yard, so privacy is a rarity.

So the simple answer is.. No.

Well, technically yes, but they aren't hot tubs. Don't people go to hot springs? Those are natural hot tubs. Then you don't have to worry about the upkeep.