If Approach NDBs ever bite the dust, and GPS approaches replace them, then it will probably have an unfortunate impact on PPL IMCR holders.
Most flying school single engine training a/c I have come across have basic agricultural instruments in fairly ancient airframes. I can't see many school owners wanting to/being able to install fixed GPS systems that meet the required standard for approaches.
Incidentally, is flying training for GPS approaches mandatory or advisory?