I did not get the meaning of your original post. Losing quorum does mean the cluster is read only. In this scenario the replicaset can be force reconfigured so that the unavailabe member have no votes and no priority. This allows the remaining host to become primary. This is not a desirable situation, adding additional member to provide greater availability is a better option.
If enough Oplog is available reconfiguring as above allows the down hosts to catch up. Removing cluster settings will make some mongodb features unavailable and yes the cluster would have to be reinitialised.