Do you have bees?

Some trees have a longer juvenile period than others, i would continue to wait. Al

One possibility that comes to mind with the pears is that some pears are pollen sterile. Have both trees been flowering for a few years already. I wonder if the tree that's producing is pollen sterile and therefore not pollinating the other tree.

Some pears are very slow to come into production. That's another possibility.

Most of my apples have been in the ground about 6 years. Only about half of them have fruited just a little so far. I suspect I met have sped things up if I had given them more care (mulching, more watering, etc.)