I don't believe the bolded is true. At least not in a way that signals some sort of seismic shift of the whole game.
The NT over the last three years has featured just three events played on a ball golf venue (at least in part): Vegas, Glass Blown Open, Masters Cup. All other NT events in that time are played entirely on "traditional" disc golf venues (parks or dedicated properties): Beaver State, Pittsburgh, Hall of Fame Classic, Delaware. Same for Worlds. Not since 2016 in Emporia has Worlds seen a ball golf venue.
On the DGPT side, there are even fewer ball golf venues. In fact, only San Francisco, Utah, and the Final have utilized a disc golf course on a ball golf course. Every other DGPT event has been or will be on a "traditional" disc golf course in a park or on dedicated/private property: WACO, Jonesboro, Portland Open, Ledgestone, Idlewild, DGLO, Maple Hill, Green Mountain Championship.
I think it just feels like ball golf venues are becoming more prevalent because they are rather heavily concentrated in the first part of the season. I could be mistaken, but I think other than the DGPT finals for which a venue hasn't been announced, there are no more ball golf venues on the 2019 elite tour (NT, Majors, DGPT).