Try visiting Perth, Scone, on a busy spring day.
Pilots responsibility through and through, see and be seen. The air/ground/ATC, call it what you will, can inform of traffic that they know about, but it falls to the pilot to keep clear of other traffic, despite what that other traffic may be doing.
Have seen it all at Perth, quite shocking in some instances
Air/ground is not ATC - they are 2 distinct ATSUs, although I understand that some A/G operators like to think they are ATC.