Loners

"loneliness has the same risk level for premature death as diabetes."

Loneliness is not the same as ALONEness.

We have a social construct/value that stresses/values being..well, sociable. That's the belied "norm", and there is little support for being a deep introvert.
As an introvert, I hear all the time well meaning people say things like " you should get out and see more people"
"It's not good to spend so much time by yourself".
" I'd go nuts if I had to spend as much by myself as you do" ( There's a telling comment).

Again, confusing loneliness with just being alone most of the time.

Many studies have been done that show introverts do better when they can BE introverts, and the same for extroverts who can be around others. It's really that simple.