Why are crabapple trees dying?

I have seem many crabapple and some regular apples that are in poor shape. They have a lot of fruit, but the leaves are not full size. There is a place I drive past that has a row of them that were there in 2000. all of these are in that condition. a neighbor has three, one in that condition, and at my office of 5 one is that way. It looks as if the fruit took over. Wondering about the cause and if these are going to survive winter.

I see them get rust and scab a lot, causes premature defoliation.

In the northeast there is an unusual apple defoliation going on not related to scab or CAR. At first I figured it was due to drought but it is occurring even with trees in reasonably moist soils. I’m not particularly worried about it but am also curious as to the why. By now trees have stored plenty of energy to get through winter and bound to full growth in spring.