It is a subject that is being affected all over the country.
Couple of things are at work. First the sources of previously unused proper gravels, stone, crushed whatever are either going up a lot in price or may in some cases not be available. For things like driveways the preferred base was a type of granite stone dust. After that probably whatever you can get your hands on cheap. Will vary with the area.
Then you have a huge demand to recycle a number of products like old concrete, stuff dug out of roadways, ditches, etc. In some cases things like construction contracts will prohibit reusing certain previously used materials. There is huge interest in finding proper uses for many recycled products even for use as a fill. Driveway fill is a good use. You can get away with using many products. Use of virgin materials is a bit of over kill.
Plus the number of quarries in some areas has decreased. The screaming meenies love to close quarries.
So it may simply be price. Virgin crushed stone of any type costs more, recycled products if available are usually cheaper. True in my area, even the types of asphalt have radically changed. The grindings from roads is being reused in many ways not formly done. Round here they are using it in place of sand on snowy / ice on roads. Fancy water based asphalt mixes.
Lot of it also is the material cost is not the big factor. Transportation of the materials is as much or more if you got to haul it any distance. So the long and the short of it is for your area, probably what is available, what does it costs, how far do you have to haul it? Nothing wrong with recycled concrete if properly prepared. Actually good use for it. Take whatever is the cheapest.
Think green, save the planet and all them polar bears, recycle where you can.