Since I've had same thing happen with both pepper and tomato plants I'd tend to agree with things I've been reading that say current heat & humidity on top of too much rain since April/May have made plants behave strangely this year.

Sorry about your eggplant...the parmigiana, grilled slices, caponata, etc. won't be the same if not made from your own garden.

Maybe if we get a stretch of stable weather they'll set fruit and critters won't get them before you do.

Try pollinating flowers yourself as suggested in this article. Worth a try of humidity breaks.

Good luck.

Here is a link that might be useful: Causes of Eggplant Blossom Drop

This is my first time growing eggplants so dont know what is par. I have harvested a couple each from my 4 plants and
there are on average 4 fruits on each plant with one plant with 6-8. There were definitely many more blossoms though.