It depends though, whom you are asking about failed or successful policies. For example I have seen a normal flat of a friend in China in a capitol of a province, who lives alone in this 4 room apartment. I asked how much rent they had to pay and then asked them what they think, how much they would have to pay for that in Berlin. When I told them they would probably have to pay some 2k EUR rent, they thought for a moment, then just said: "That's insane!". The rent they paid was maybe 1/8 to 1/6 of that. And that apartment was not somewhere far out. It is well within the city and has good public transport connection. People can afford to rent. People can move. Single people. Over here not so much. This is also a result of the state having built houses and apartments.

i don't know much about the rental market in china, but living there, always renting, i had the impression that rents do not cover the cost of the apartment. it is as if most people rent out their apartment because it would otherwise stay empty. when we finally bought an apartment, the mortgage payments were twice as high as what we would have paid for the same apartment in rent. we had a 15 year mortgage i think, so that means it takes 30 years in rent to just cover the cost of the apartment. is that profitable? i don't know. in germany rent has to be profitable.