For what it is worth, we attempted to do this for Iron. We fell short because we couldn’t get all of our tests to pass with localhost only as the default. You can see some of our working on this in Proposed changes to how ROS performs discovery of nodes , and Improve handling of dynamic discovery · Issue #1359 · ros2/ros2 · GitHub and Sloretz/test discovery by sloretz · Pull Request #512 · ros2/system_tests · GitHub .
So in order to get there, someone would need to spend the time to figure out exactly what doesn’t work in which combinations, and then see if it can be fixed. The ROS development core team probably won’t have time for this before Jazzy, since we already have the switch to Ubuntu 24.04 and rmw_zenoh_cpp on our plate.