The amount of space taken up by car parking makes me generally unsympathetic to complaints about bike sharing "taking up too much public space" - though perhaps there is less car parking in china.
That's 40 km/h. Are you trolling or is that a typo?
I've been bicycling nearly daily for >45 years and I've never gone that fast.
I cycle to work daily (22km) and have cycled pretty much all my life since. Sustaining 40km/h for longer periods is unrealistic if 1.) your terrain is not completely flat; 2.) there is wind; 3.) you do not want to get to your destination soaked with sweat; 4.) you have to carry some luggage like a laptop; or 5.) you cannot use a touring bike because of the terrain.
I sometimes cycle with a GPS and have Pedelecs (limited to 25km/h for electrical support in Germany) as a reference point. The vast majority of cyclers that I encounter cycle less than 25km/h under normal conditions [1]. Probably somewhere between 20 and 25. If there is strong wind or uphill, it's definitely less than that.
My 20 km/h includes a few stops and normal traffic so it's probably closer to 30 on a flat straight with no traffic. Perhaps a special bike with narrow tires could help, but that's less versatile (and I need to ride on dirt roads too).
The highest I've measured is 54 km/h, on a big down hill pedalling full strength on top gear. I regularly exceed 30 km/h but not for sustained periods.
I could probably do 40 km/h for 15-30 minutes if I went all-in and had a racing bike. But my commute includes dirt roads and pathways through the forest so a racing bike is out of question and I don't want to take a shower every day arriving to work.
I don't really have to share the road with cars at any point on my commute so driving too slow isn't an issue. A part of the way is shared with pedestrians (and slower bicyclists) so going too fast is more of a problem.
I've used a good recumbent bicycle and I could actually hold 35 km/h easily in that one, in the same place I usually average 23 km/h upright with an ordinary ~$700 city bike.
These are mostly 2-lane country roads, with 6 foot drainage ditches on the sides on the roads instead of sidewalks, and sometimes even large delivery semi trucks drive these. You'd have to be crazy to ride a bicycle on such a hostile road. I did so twice and my mother refused to let me bicycle to work, insisting I use my father's car.
There is a huge difference in both perceived and actual safety between being part of a large group of bicyclists that occupies a significant fraction of the lane and being a lone bicyclist going along the verge of the road while cars and trucks pass you at 65 mph.
In some developed cities, but in most of China cars are usually parked on the sidewalks. When they're angle-parked along the full width of the sidewalk, pedestrians need to drop onto the roadside to continue walking.