...but people are powering down and leaving for other projects.

The numbers tell a different story, since September 16 a total of 4,797,406 steem has been powered down but 8,071,648 has been powered up so you are incorrect. That is net positive of 3,274,242. Yes some people are leaving but that is to be expected if the bid bot users and serial spammers can't milk the system anymore.

I was expecting the price to go lower but it has held up very well especially against bitcoin until yesterday (but that has more to do with day traders jumping on the BTC pump and has nothing to do with the conequences of HF21/22).

The drop in price on September 24 also has nothing to do with the changes from the last hardfork. That is when BTC dropped from almost 10k USD to 8K USD.