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Sometimes it just can't be explained; a tree death. You did however suggest some extreme weather that certainly likely played part in losing your tree.

https://www.gardeningknowhow.com/ornamental/trees/tgen/sudden-tree-death-causes.htm

It could be fire blight which is not good news. Here is information on how to control it. You might also contact your local extension agent for absolute diagnosis.
https://www.gardeningknowhow.com/plant-problems/disease/fire-blight-remedies-and-symptoms.htm
https://www.gardeningknowhow.com/edible/fruits/pear/pears-and-fire-blight.htm

Some pear varieties don't ripen on the tree. They are hard when picked and ripen during storage. Did you see this article on types of pears? You may have an oriental hybrid. Read more:
https://www.gardeningknowhow.com/edible/fruits/pear/types-of-pear-trees.htm

No don't prune them drastically. But you may consider transplanting them into a better growing situation.

The fact that they are planted in a lawn area may be part or all of the problem. Competition for water and nutrients with grass is significant. The high nitrogen fertilization that grass requires will stimulate vegetative growth at the expense of flowering and fruiting.

The best growing conditions for fruit trees is a designated planting area free of other plantings, where you can irrigate and fertilize appropriately, specifically for the trees, and mulch the soil surface.

https://www.gardeningknowhow.com/edible/fruits/pear/getting-a-pear-tree-to-bloom.htm

I would be looking toward testing your soil. It is likely that the soil is missing some nutrients, namely phosphorus and potassium, or maybe has too much nitrogen. Both of these can cause a lack of flowers.

This article will help you to find your closest extension service that will be able to test your soil: https://www.gardeningknowhow.com/extension-search

This article will give you more information on other causes to this as well: https://www.gardeningknowhow.com/edible/fruits/pear/getting-a-pear-tree-to-bloom.htm

Pears require a number of hours of chill time. Is it possible you had a mild winter on the off years? Also, too much fertilizer will result in lots of foliage but no pears. You don't mention any signs of disease or insects, so it may be something environmental. Lack of pollination is also possible. Here is more information:

https://www.gardeningknowhow.com/edible/fruits/pear/pear-chill-hours-for-fruiting.htm

https://www.gardeningknowhow.com/edible/fruits/pear/pear-tree-pollination.htm

https://www.gardeningknowhow.com/edible/fruits/pear/fertilizing-a-pear-tree.htm