[1]: https://www.aopa.org/advocacy/airports-and-airspace/navigati...
"Most" VORs are not being phased out. The FAA is going from around 950 to about 590: about one-third are being retired.
Furthermore, no one is making the receivers anymore. If you have an NDB needle in the panel you are flying an airplane with some awfully old gauges....
The reason is that you have to practise doing relative bearings and wind corrections in your head, or else you fly in a spiral towards the station (unlike VOR, which displays absolute radials.) That means you will be off the protected approach path, and can hit obstacles.
If they could fly an ADF, then AM radio stations can be used if necessary. (Airlines used to pay local radio stations to do a station identification announcement upon a phone call from ops, with the radio station typically near a coastline.)
Just don't hit the radio station antenna!
Note that NDB and VOR approaches are non-precision, which means they have lateral guidance but not vertical. So with low clouds, you won't get descent info to the runway like ILS.
That's a big deal for airlines, since they have company operations minimums that may not even allow NDB approaches, which are more restrictive than standard Part 91 (GA) operations minimums. For example, there are situations where I can takeoff in a Cessna with 0/0, that airlines can't.
Great discussion forum on navigating using radio stations:
https://www.pilotsofamerica.com/community/threads/commercial...
Source: commercially-rated airplane pilot.