I think part of this feeling was mentioned very early in the thread but got lost. It used to be very common for the price of kosher chickens and meat to rise significantly right before chaggim for no discernible reason .
For Pesach it was worse. About 20 years ago, the price gouging for non meat was exposed by a Long Island supermarket in my town owned by a non religious Jew. He had opened a brand new building across from his old one about a month before Pesach. His lease on the old store, now empty, still had two months to run and someone gave him the idea of a Pesach superstore. When he saw what the wholesalers were charging ,for the same canned and paper goods he bought all year, he couldn’t believe it. He demanded that they charge regular prices unless they could justify the significant increase. They couldn’t and charged him regular prices and he passed those savings on. When I called my Brooklyn friends and they heard about it, they drove out and saved significant money.
I can still remember my mother complaining about meat prices. My uncle was a shochet in the Midwest and he would tell us that shechting was the same all year round and butchers could raise their prices because they could get away with it