Here in the US, the talk is all about Performance Based Navigation. As airspace gets tighter and they seek to pack more airplanes into less space, the Required Navigational Performance for entry into high traffic density airspace will demand ever increasing navigational accuracy from each airspace user. In concert with ADS-B, more stringent RNP specifications are expected to increase capacity in the US National Airspace system. Just about all the countries in question have announced plans to eliminate VOR and ILS system support from their infrastructure budgets and redirect those funds to GPS/GNSS based ground equipment such as WAAS/GBAS and ADS-B related equipment. All resources will be directed toward a single NAV source if they proceed as currently planned.
The national aviation authorities in Europe, North America and most of the industrialized West are working in concert with ICAO to develop and undertake these initiatives. The date for ADS-B compliance in the USA has slipped to 2020, but the FAA claims it will slip no further. No GPS, no ADS-B. No ADS-B, no flying in most major terminal areas or the surrounding airspace. PBN, RNP, ADS-B... It all adds up to allot of currency any way you look at it. And training fleets, along with private pleasure craft face the biggest burden of all if one calculates the compliance costs as a proportion of aircraft market value.
THere's no getting around the fact that a way will have to be found to equip the training and private fleets with the new gadgets and train everyone to properly use them. The alternative is obsolescence and extinction except perhaps in a few remote areas. Good luck Europe and UK!