The Mainland hasn't been supporting Hong Kong as much as taking it over and adding to it's historic role as a gateway for FDI into China, it is now using it as a gateway for businessmen and CCP to ship money out of China into safe assets (into Hong Kong and overseas).
What the CCP has done to Hong Kong is basically neocolonialism.
Yesterday I talked about just that with an HKer who works in marketing. Democracy supporters acknowledge that this trend is hurting the economy, though on bright side they welcome businesses starting to target local long-term customers more.
The number of restaurants and bars I see closing on an almost daily basis is getting sad. My friends in the F&B industry here confirm that they're hurting. Bad.
Hospitality is hit even harder with hotels at 30% occupancy and many having to offer rates at 50% or higher discounts, and having to lay off staff.
If the CCP had let HK be autonomous as they agreed this wouldn't have happened.
So it's not exactly altruistic support, but the economic entanglement means that if the mainland decided to embargo Hong Kong, the effect would be devastating.
People who support CCP believe that it is the greedy capitalism caused the problem. Implementation of the CCP regime can rebuild HK. People who support democracy believe that it is the CCP iron fist caused suffocating.
No one is backing down. It ended up with a civil war.
Humans repeat their mistakes generation after generation.