So DHT robustness against censorship is superlinear of the number of participants.
The "break point" is when a DHT gets big enough I can't realistically MITM all the links with nodes "closer to the target" than existing ones.
This means big networks are great, small ones are cheap to just break. Its hard to skip the messy bootstrapping phase.
I'd encourage protocols to only rely on DHTs for small key-value stores if there isn't a trust mechanism in place to validate new peers.
Otherwise, all I have to do is mine for O(n^2) dht keys that cover the network. Figure out what your key mining difficulty is and you can identify what the cost would be.