The question is why have you switched to primary donate? I did it to build muscle memory for tech training. If all you are doing is recreational diving primary donate is counterproductive as it goes against recreational conventions and norms.
I have been seeing a little bit more primary donate from OW/AOW divers in San Diego. Not up to 50%, but probably at least 20%, maybe more? Some of them are visiting divers from back east and a very small sample size. Of course, we get a lot of folks from New England, maybe it's taught more up that way?
My training from zero to hero (AOW-> MasterDiver) was all primary donate, but I think that's because quite a few of the local dive shops here have a large tech business?
If you have an Air 2 or whatever on your BC, does that mean you do primary donate? I've seen them but never dove with anyone who used one.