Something we could say though is that the STEEM initial distribution came from proof of work (we could argue fishy mining bug and the few participants but anyway). The ninjamine was something around 80% at the beginning while at the time of the attack way down to 30%, the nature of this system is that with time more and more stake goes in the hands of new accounts.
Of course then you have people just selling right away all the rewards etc but we can’t really force users to stay vested just to have a perfect DPoS system to show off.
Other DPoS and PoS systems have way bigger problems than Hive as there’s no way to redirect inflation to new users joining like we have here and I admit I would not put a dime in them.
As for Monero, it had a mining bug too coming from Bytecoin that lasted I believe 2/3 weeks before they fixed it and we don’t really know due to its privacy how many coins people who exploited the bug could get.
So yeah in conclusion, nothing is perfect, but Hive works pretty well compared to other DPoS systems where I totally agree with your arguments.