Ridge, we’re to New Zealanders, what Mexico is to Canadiens. A cheap place to hide after they’ve made their money.
Honestly I don’t think the diseases which travelers carry here represent a significant expense. I agree with coatimundi, a lot of it is down to our life styles. Also the for profit nature of our system. If you compare the price of medicines here to any of the Nations which scored above us it’s pretty obvious we are over paying for these items. Poor lifestyles cause us to require more care, and to experience more health issues which require the more expensive medicines. The only barrier we have to care is the insurance we have or don’t have. If you have insurance they decide what they’ll cover, and won’t cover. This is for the general population. I assume wealthy folks can buy any insurance they please. If you are denied a prescription you of course have the option of purchasing it yourself. But for medical test the cost is prohibitive. Which explains why the insurance company didn’t want to pay either.

If you don’t have insurance you can foot the bill if you are able or do without.
So, an insurance company is acting as the gate keeper to our healthcare system. Most Physicians are trained to check with your insurance before they prescribe treatment. Which protects you from showing up for a test and being asked for your credit card. I’ve had the hospital call me ahead of time to tell me what by out of pocket is going to be for an MRI.
ATB
Of the Kiwis I know here, some are wealthy and some are not. They’re here because this part of the U.S. is in the “green fescue” belt and also in the “Bermuda belt”; ideal for raising livestock (kind of a complicated subject, and another story entirely), and because land is incomparably less expensive here than it is in NZ. I have heard them say you can’t buy land in NZ and make livestock work out financially. Only those who already own it can do anything with it, and the quantity of useable land is pretty limited besides.
I would disagree with you about the health conditions of many of our recent immigrants. I know medical people who treat them, and there are a number of serious health problems. One of them is antibiotic-resistant bacterial strains they brought with them. Why antibiotic resistant? Because in their home countries you can buy the most powerful antibiotics (just as one example) imaginable over the counter without prescription. And they use them to self-treat all sorts of things they’re not designed for, don’t take the proper regimen when they are the proper thing, and don’t know how to deal with drug interactions. The health toll of that alone is very significant.
In much of Latin America, the diets are poor from birth, the diseases and parasites people deal with can cause lasting problems when they’re young, and because of utterly mistaken notions about what to do if you have “X” symptoms. Those people bring those things with them. Sometime it would be interesting for you to look at the “traditional” diseases in the back of the DSM. It will make your jaw drop to see what some people believe about medicine and what they do about medical conditions. Did you self-diagnose “Impacho”? Well, the remedy is to take Cipro or whatever else you think might work, and stop cheating on your spouse.
Any health provider who deals with recent immigrants from relatively primitive places will tell you the neglect of serious conditions is appalling. You have high blood pressure? Well, you’re less of a man if you chain yourself to medicine every day. You have diabetes? Well, that’s what “white” doctors tell you so they can sell you medicine and keep you coming back and change your diet to something you won’t like.
Many immigrants have been exposed to very serious environmental hazards, sometimes over a long period. Most of the first world is pretty clean of such stuff, however little environmentalists think so. But in much of the world, environmental hazards are pervasive and serious, and people are exposed to heavy metals, incredible air pollution, even radiation.
As to overpaying for medicines, there’s some truth to it, though not totally so. I have, in connection with part of my occupation, had occasion to investigate foreign-produced drugs. Most of the cheap ones are analogues; some even made by the same pharmaceutical companies that make our own. There are differences, more often than not; some of them significant, some only more or less convenient. And they’re very often made in places one might question, even when they’re made by a first world pharmaceutical company. Dig into some of those Canadian mail order drugs and you’ll find that a lot of them are made in places like India, Thailand or even Vietnam, no matter who the company is. Maybe it’s wise to trust your heart to statins made in Bangladesh. Maybe not so much.
And somebody is going to be the “gatekeeper” for treatment no matter what. People aren’t too fond of insurance companies doing it. But one has to ask oneself whether they really and truly expect the government to do a better job of it. The only healthcare system in this country that is NOT actually operated by insurance companies is VA and, well, that isn’t a system to write home about.