It's hard to say, an early version of a GLS (GNSS LANDING SYSTEM) of which GBAS is the most recent ICAO developed version, is in place at some airports in Norway.
It is called SCAT-1 (special category 1), only one or two operatos ever upgraded their aircraft to use it. ILS exists at some of those airfields as well.
GBAS is still very new technology, I only know of Honeywell that makes the ground equipment and Honeywell and universal are the only two FMS providers to make compatible equipment last time I checked on its progress.
15 years will only be enough to see a parallel operation of ILS and GLS.
Plus aircraft even down to the Citation II, King Air size are unlikely all to be fitted with Dual FMS and VHF datalink receivers. They will want an alternative in the form of ILS. But VORs and NDB should on the verge of extinction by then.