Is there some type of mattress conspiracy?

Why don't mattresses last as long as they used to years ago?. All of a sudden all you see on the side of the curb are mattresses tossed (dragged) lol to the garbage. Years ago people would owned thier mattresses for up to 20 years. So was that bad on our bodies? Or the fact that they now make them nonreversible. Sorry for the rant, but I'm mattress shopping. This whole week.😑 I refuse to shop at sleepys again.