Under the current system we can rugpull the savings accounts anytime we want

The "we" here means the HIVE community, not some top down "HIVIAN RESERVE BANK". When HBD is pulled from savings en mass, that nice interest rate would have to be adjusted way down. It's not like there's some HIVE dictator is waking up every morning, looking at the numbers, wondering when to pull... sort of like it feels like with fiat.