Would single payer- like Medicare for all - result in longer lives and lower death rates for Americans?

Yes --- look at the lifespans in Europe and Canada (which have medicare for all) --- they are longer than the average U.S. lifespan.  Granted there are other factors, some americans have been known to engage in riskier behavior and eat lousy diets, but single payer health care is one contributing factor to the gap.

edit: Susie: Acknowledging that single-payer health care exists in those countries doesn't imply that there aren't supplemental policies.  Thus there's nothing false in that statement.

It didn't in Italy.

yes, you bet it would.

There's more to it than just medical care.  Housing is an important right that's part of good health, too.  And clean air matters.

it might do that