you might have election ballot, but no bread from central goverm

You ask the right being elected, not the right to vote. You intend to confuse the people with two rights. The central government can grant the right, but, in the same time, the central government can stop supplying the blood to HK, and let your guys use the ballots to warm up your house and fire up stoves. The central government need to have the face saved, so even it wants to give you, but, for the face, you have to wait for some years.

HK is not the place for bargaining something. HK has no resource to bargain for. It is the place that can be easily manipulated by central government economic policy. To gain the favor from central government, it has to do things the central government likes. Crying baby without loving face won't have candies.

Central government has more chips to bargain with US to cut off the support of those protesters at this time. Without US support, those protesters will go home very soon.