I'll concede that the comment was vague and relied too heavily on a shared intuition. Though I will admit, the reward became well played dry comedy throughout your sibling comments.
So I'll break down my reasoning a bit. It requires a full blog post to get out, so please forgive the abridged version.
Healthcare is a catch all for all the other problems of society. The top costly conditions in the US are (in order of this barely sourced article): Mental Disorders, Heart Conditions, Trauma-Related Injuries, Diabetes, Cancer, COPD and Asthma.
Every single one of these is plainly racking up unneeded costs by the daily actions of all of us. My quip on the supermarket was a remark on the total view of health (from mental to reproductive care to basic carcinogens to ...).
How many people are mindlessly scrolling on Instagram while performing another task, how many people smell of cigarettes, the marketing of 'sinful goods' (depending on the state), the near impossibility to avoid added sugar in every packaged foodstuff, the number of 'alcohol noses' you can see down a 50ft isle, the parenting of children, the smell of fossil fuel exhaust from the parking lot, the gait of the elderly, injured, or soon-to-be, the accommodations (or lack thereof) for those in wheelchairs and with living assistance, and still the primary food at checkout - And to include everyone in the conversation: think of the anyone working two jobs and has 0 time to prepare fresh food for themselves or anyone else, the eventual cost is in the habitual behaviors made in the constraints of under-compensated labor.... I could keep going and I've left out other observations contributing to other conditions but I think you understand.
The thing I'm trying to say is that there are interventions all over the place - however, the up-front costs (ignoring all else) of a 'double blind randomized trial' for every single one of them to earn the proper authority to define its relative utility to cost is unrealistic at the moment (also most governments do not allow for risk based price of care) - an economic externality.
Couple this externality behavior with a market of near perfect inelasticity for good health (and before someone comments, yes, suicide / assisted euthanasia may not be inelastic in price on this metric) - and you can't say "Healthcare is such a base layer of the economy" - an alternative analysis is "Healthcare is an externality that is priced in a government controlled market"
[Edit] I completely left out the externality of the high reward litigation industry on malpractice and all of the above conditions as evidence of harm - adding pressure on compensation to the highest paid professionals.