bike shops around the country are being shutdown as people no longer buy/upgrade/repair their own bikes, they rent one for 6 USD cent each ride. you see less fun/cool/stupid/crappy bikes on street, they all look the same now.
do they reduce emission? well, rather than walking to the metro stations to catch metro people now ride a mobike/ofo to catch the metro, I don't see any reduced cars on street. There is no stats to back the reduced emission story at all - otherwise you'd be seeing them pointing to those figures jumping up and down on daily basis.
do they make cities better? well, see photos below, remember - they don't clean up their mess, they just deploy their tens of millions cheap bikes onto your streets.
http://img.mp.itc.cn/upload/20170327/3e5e188412ef46ca892d20f...
http://s2.imbiker.cn/201705/22/b25b38ba8cda6df9c686657044f48...