Jack: There are two possible causes for this, alone or in combination. First, for most people in the northern Willamette Valley region, pears and apples produced very heavy crops in the summer of 2023. Most apples and pears are prone, to some extent , to alternate bearing. The genetics of the particular variety determine how strong that tendency is. In some it is very strong (Gravenstein and many others) and some that rarely show it at all. Bartlett pears are sort of mid-alternate bearing trees. One reason to thin a heavy fruit load within 30 days or so after fruit set is to reduce alternate bearing.  Also, on a vigorous tree, doing some summer pruning (late July through early August)  will help even out bearing cycles. Persimmons are also prone to alternate bearing.

The other issue was the weather we had this past spring. There were a few good pollination days and cycles of a week to 10 days or more where it was cold and wet. Some mason bees were out as well as honey bees later in the spring, but it your tree bloomed right in one of the poor weather cycles, it didn't get pollinated or the wet, cold conditions actually led to "set" blossoms dropping from disease. 

My sense, if the weather cooperates, next year should be good. 

I hope this helps. Chip Bubl  OSU Extension Agent/Columbia County (retired)