If I lived in the olden days, and had to wash with soap, I would be crying for sure. I have experienced the feeling of soap and hard water and do not care to feel that again. But no, I am not a slimy person walking around under a thick crust of soap scum, because:
We Do Not Use Soap in my household. Because yes, it does not rinse away in hard water. No natural soaps of any kind. Detergents do fine in hard water. We use body washes but never anything with actual soap. I banned soap twenty years ago. I don't know why they even sell it in Florida, it does not work here.
I just think of hard water as mineralized water, and soft water as plain water, and softened water as slimy. As long as we use the right products I think it's fine. I grew my hair way past my butt undamaged, if hard water was damaging it I think it would have showed up on the very old hair.
And we aren't walking around peeling and stinging and scabbing, I'd notice that!