A neighbor’s one Apricot is loaded with fruitlets–probably as many, or more, than are on my two Apricot trees.
I hand pollinated probably a thousand flowers (and, afterward, lots of pollinators were spending lots of time and energy on the trees), but I think the late frosts destroyed the majority of them–but you would think the late frosts would affect my neighbor’s tree in the same way.
Could it be that her tree fared better because it has all-day Sun–that, maybe, the soil absorbs more heat during the day, and is able to warm the tree, and then the tree and its soil get warmed sooner, and more consistently, because she has no shade?
My trees get Sun from the time it rises to ~9:30a, then are shaded until ~12:15, then are shaded after the Sun goes behind the mountain at ~6p (her trees also do not get Sun after this time of the day).
Also, she cheats 
–she has sugar water deployed for the humming birds, so they spend a lot more time on her property, so, maybe her trees set fruit earlier, and the fruitlets were able to survive because of that maturity?