You had better hurry up . With the introduction of ADSB all ndb and possibly vor stations will be decommissioned and the VFR pilot had better invest in GPS .
The is no indication that the published list of backup VOR AND NDB beacons will be reduced any further.
In fact I have heard a rumour that the US is looking at increasing its land based navaids over concern that the US military may re-introduce dither to the GPS network.
If you are satisfied being a hack pilot, then following the magenta line will get you there. If you aspire to being an true airman then you will want to understand and be able to use all the tools in the box.
ADSB is not a navaid. It has nothing to do with the decommissioning of ground based navaids. Nor does it provide enhanced safety in the context of the Australian implementation. Nor is it required for VFR. ADS-B is a tax on IFR flying created by Australia which is the only country in the world that is mandating it for all IFR flight in all airspace types at all altitudes.