I have flown sailplanes that had all the avionics they did when they were built in the 1950s. And others that had 'modern' technology like electronic varios and a comm. None (so far) have had a transponder, FLARM, ADS-B, Bose sound or XM satellite.

Recently, I read a comment (elsewhere) from somebody who thought all of that (except for the Bose) should be mandatory equipment.

Nice to have? Sure. But mandatory?

Why not move in for the kill and just ground everything built before 1990?