A girl I dated in high school in the 70s wore bodysuits every day, always with hip hugger jeans. Looked great. I don't understand the references to high waisted pants either. I guess I never noticed. As far as men wearing them I can't say I heard or knew of a single one. So my guess is that it never left the starting gate.
We have tried to buy many on line for my wife but most go straight to the thrift store donation box because the size charts and fit information are horrendous. It's too bad. Because on the rare occasion when she finds one that fits they look great on her.
Almost always they are too short, no matter what the size chart says. She's only 5'4". They also have no elastic in the legs. So if they are long enough then they are droopy and baggy around the legs. And the legs are often cut way too high so it turns into a thong even if they don't call it that. Something she doesn't care for. I can't understand why big online retailers seem oblivious. Sometimes their bodysuit size charts don't even provide a girth or torso measurement. Really? What are they thinking?
The best fitting one she owns came from a dancewear site where most of these problems are addressed. Swimwear and dancewear manufacturers have addressed these problems for decades. So it doesn't seem like rocket science.
It seems like there is a market for an online retailer who carefully
addresses the poor fit issues caused by the online shopping experience
and who charges a little more to do some real quality control.