You can operate your stellar-core in two modes, validating or observing. If you are in validating mode you are both listening and participating in consensus.
But semantics aside, in Stellar anyone can participate in consensus. As in anyone can both listen and talk. It is true that maybe no one else will want to listen to you but there is certainly no barrier in the protocol keeping people from talking. And again if there is some cartel or some group that people feel are getting too much control it is trivial to set up your own nodes that are fully participating in consensus and have the non-cartel nodes listen to each other.

Also I'm not sure what people have in mind for the IETF ILC thing (I haven't had a chance to catch up on what is being discussed/proposed) but you can also easily have multiple independent stellar networks.