Not an expert this is all just observation and conjecture.
Seems to me it's largely a mix of temperature and wind during pollination.
I figure a hard freeze can kill the buds and recently fertilized embryos just like it can kill other mast-producing crops. I've seen that happen a couple years notably 2020 we had a hard frost + snow in mid-May and that year was as barren as I've ever seen.
I also believe a really rapid spring greenup can cause issues, as I believe happened last year. 2021 we had a super early, fast and hot spring and the whites last year were spotty and same with reds this year. Whites produce fruit the same year, reds take 2 years. My guess is that just throws off everything's biological clock so pollination isn't as synced up? The fact that I spent ~2 months cleaning pollen off my house and car that spring would seem to indicate that vs. the normal ~2 weeks.
Oaks are wind pollinators so if you get a couple super calm or super windy days I think that can also influence pollination, possibly causing some trees to bear but not as heavily as they potentially would.
Within those factors even in the same area I often see oaks producing vs. not at different elevations. I think they probably bloom at different times at different elevations and the ones that have good conditions produce. Frost also impacts things differently at different elevations and the valleys usually frost up first thus why apple orchards have to be located higher up.
After pollination, they can experience drought or pests and we had both this summer with gypsy moths and no rain in July. Those trees now are not healthy not only this year but going into next year too so who knows what that means, some trees invest all their resources into a last-ditch reproduction effort and others will not.
