Why are berries so expensive?
It is a combination of many factors. To sell you one perfect apple, one perfect bunch of bananas, or one perfect half-pint of berries requires:


the land to grow on
workers to plant, tend, weed, and pick
transportation to market
loss allowance for fruit that's bruised or spoils in transit
loss allowance for fruit that spoils while at the store and people won't buy it


Many of these factors are objectively higher for berries than for applies or bananas, especially given their short shelf life and tendency to bruise.

This puts a floor on the price growers and stores can charge. Then on top of that, they are delicious and healthy, so at least some people will pay that price. This removes downward pressure to sell them at a loss to get you in the store.

A better question is what can you do about it? The answer is generally to use frozen berries (they don't incur the spoiling and bruising losses) or to eat berries only when they're in season locally and eat other kinds of fruit the rest of the year.