The question of authenticity strikes me every time I walk through a hutong recommended by a guide book. These are, without exception, hutongs which have been converted into food and bar streets. They are crowded with Chinese youth and tourists. Nothing remains of the original hutongs. Those are full of local life, children playing in the streets, older people sitting around, men and women going about their daily life, chatting. The repurposed hutongs are dissociated from the life of the city, and look like a bar street anywhere else in the world, sometimes glitzy, sometimes sleazy, like the photo above.
They satisfy a notion of conservation according to which authenticity resides in the material. The notion that change in usage can render the neighbourhood inauthentic does not strike the self-congratulatory guidebooks.