But putting that aside, I too found the claim implausible and went looking for data. Here is what the CDC has to say:
Leading Causes of Death
Data are for the U.S.
Number of deaths for leading causes of death:
* Heart disease: 659,041
* Cancer: 599,601
* Accidents (unintentional injuries): 173,040
* Chronic lower respiratory diseases: 156,979
* Stroke (cerebrovascular diseases): 150,005
* Alzheimer’s disease: 121,499
* Diabetes: 87,647
* Nephritis, nephrotic syndrome, and nephrosis: 51,565
* Influenza and pneumonia: 49,783
* Intentional self-harm (suicide): 47,511
[1] https://www.cdc.gov/nchs/fastats/leading-causes-of-death.htm> The Johns Hopkins team says the CDC’s way of collecting national health statistics fails to classify medical errors separately on the death certificate. The researchers are advocating for updated criteria for classifying deaths on death certificates.
https://www.hopkinsmedicine.org/news/media/releases/study_su...
I don't know if this is credible or not, but it's coming from the John Hopkins School of Medicine which I think is broadly credible.
Assuming for a moment it is, what would be the impact to life expectancy if nobody went and saw a doctor?
The parent's point was that, unlike in Europe, when someone is injured by no fault of their own, the expected way for them to pay for the (very high) medical costs is to sue the offending party.
That's the excuse for not offering universal healthcare. Incidentally, it also explains why the doctors need insurance (because malpractice does happen sometimes, and if your health is damaged by it, you won't get a nickel of support unless you sue the offending party - i.e. the doctor).
That wouldn't be such an issue if we had universal healthcare and a support net for people who can't work.