Becauase the prices of those commodities, produced in the global north, are generally kept high bc the wages paying the people doing are kept high. In addition, theres a lotta expensive equipment thats much more availible in the north than south, and anyone caught doing medical treatment below these high, expensive, standards (or without a license) is imprisoned.
Also bc, yknow, in socialist countries that welfare is actually a concern. But you'll also note that AES puts a lot more emphasis on preventative care than expensive treatments, when possible, because unlike in capitalism the goal isnt to wring out as much money as possible.
I'd also note as this is the marxism comm, "healthcare" isnt rly included in "value of labour power". Value of labour power is the value required to allow the proletariat to exist, not to exist healthily. If the proletariat, as a class, continues to exist i.e. can afford sufficient food and shelter to not literally die—that is what capital considers the minimum value of labour power.
Costs of living are actually lower in terms of percentage of wage in the imperial core, as I said in original comment (as as Cope shows with numbers both for wages, costs of necessities and hours of labour to earn necessities)
Cope has read all three vols of capital and cites and engages with them extensively fwiw. He is aware of Marxs arguements and in fact cites Marx extensively to support his arguments. I would suggest reading the Cope book bc, tbh, you could probably follow the maths better than I could. He takes all your points into account and directly refutes them (some of them even in the two prefaces). It felt like reading Marx, in terms of his thoroughness.