I heard from United that due to costs, they are letting quite a bit of the RNAV drop off, as they seldom get cleared by ATC for an RNAV APP, and virtually never for the RNAV DEP.
You sure it's not the other way around? While most of the airports main line carriers go to have ILSes and ATC is spring loaded to clear you for the ILS, I'd say half the departures I fly going the same places United does are RNAV.