And with reference to "stand-alone" GPS approaches. Just to put them in perspective. At the airline level, my company which has operated 777s for 10 years has JUST received approval, with a number of caveats even then, for "stand alone" GPS approaches. We need that for ETOPS alternates like Midway.
And we have the mother of all nav systems to back up the two GPS systems. The ADIRU with its many IRS and fiber-optic standby back up IRUs would by itself be more accurate than almost all non-ILS approaches. And we have 2 active FMCs and all manner of cross-checks. On IRS alone we can navigate for 12 hours without any other updating.
And yes, I am old enough to remember the "old" days when we didn't have all that gear and you have to have positive ADF station passage, or passing over a VAR Marker (remember MONEA up near Mangalore and the "Z" marker at HBA? etc).
There's just no substitute for knowing where you are, as PIC, before you let down. If I ever have to go into Wake or Adak with one engine out, ATC will be the people I call on SATCOM after I land, not someone I expect ANY help from on the approach.