DPoS might seem vulnerable -in the case of steem it was- here it is more difficult for one to takeover the chain, but we've seen what the community can achieve when they rally together, but also when they have to do with bad actors.
Which reminds me that we need to make an in depth discussion all over again so that the chain will be bulletproof against any kind of threat.
I feel like time and distribution of stake will be the ultimate answer. As much as this is uncomfortable for some people, the large holders who only extract value, need to have that rate of extraction minimized, so that value creating stakeholders of the future can grow their relative stake.