The Hong Kong executive is a virtual puppet. He/She cannot make important decisions without the approval from Beijing.
China is in a tight spot here, because they need the access Hong Kong gives them. Many wealthy party members have millions and billions invested in Hong Kong as a safe haven.
None of them want the same system in Hong Kong as in the rest of China. It erases the safety of their holdings there.
As for pushing for more...
The Chinese Communist Party can only be pushed so far. Take what you can get, which is restoration of the status quo before the protests.
Thanks. That would have been my take as well, but then I haven’t followed the leadership’s connections to Beijing closely enough to address it with total confidence.