The US uses a different definition for infant mortality than the UK or any other European country. (One major difference is whether a borderline-nonviable birth gets counted in the infant mortality or stillbirth column.) The raw numbers are not directly comparable. Correcting for the expected effect of difference in definitions, the UK still has lower infant mortality than the US overall, but by a far smaller factor.

>> For the entirety of human history, up to and including this point, it hasn't been.

> For the majority of human history, health care was done by village shamans etc (that did actually treat most ailments they could) for free.

Would you be OK with universal shamanistic healthcare? Because I don't think that would count as succeeding at "keeping your people healthy" by any reasonable definition. My strong hunch is that village shamans could successfully treat far, far fewer aliments than you could with OTC medications and first aid supplies.

Things start getting expensive once you try to be more effective than that.

And the shamans almost certainly weren't doing it "for free," but a village like that almost certainly is primarily a non-market economy, so their compensation could be obscure to modern eyes (e.g. for a more modern example and easy-to-understand example, Jewish priests were compensated by being entitled to a portion of religious sacrifices).