I'm not saying it necessarily applies for life-saving treatments AFAIK, but not everyone agrees on what medical care is. For example, in the U.S. it has been shown that state abortion restrictions hit the lower-income segment much harder precisely because they cannot afford to travel to states which have more liberal laws concerning abortion.

Or the cost of flying and getting surgery abroad is far cheaper than doing it at home, with minimal additional risk.

It doesn't have to be a rare disease—it can just mean that non-basic healthcare is hard to access.

Example: I live in the Philippines. Its healthcare system is affected by two things: centralization and the fact that the country is an archipelago.

Most quality health care is happening in Metro Manila. What you find outside is generally very basic, and even in 2nd-tier cities like Cebu or Davao they may refer you to Manila for something you'd think they ought be able to do.

With travel by boat being … rather slow, with vacation time not exactly ample, and the average salary being low I'm quite certain that affordable flights ($25 Cebu - Manila) are making ample difference in terms of what kind of healthcare situations are being addressed.

So healthcare would have been better in the outer regions without cheap air travel?

It is common enough that there is an entire organization (Angel Flight) dedicated to it. Using private planes and private pilots which are significantly less safe than commercial.

Another example is family members overseas. Many have to choose between providing for their family vs. being with their family. Affordability of flights can have a huge impact on their quality of life and ability to take part in the moments that many of use take for-granted.

This is partially self-inflicted. Cheap air travel incentivizes more people to move overseas because they know their families are just a flight away. I once knew a person that lived and worked in the UK, but studied in Poland - she flew back and forth twice a month(!). I guess it would be fine, if not for the environmental costs.

Anyway, I have this feeling that you could justify just about anything if you dig for nth-order effects, but it doesn't change the fundamental point: a race to the bottom sacrifices everything that can be sacrifices. Environment is usually the first victim, quality the second, but safety trade-offs are eventually made too. At some point in a product category's lifecycle, one starts to wonder whether it's so degraded that it would be better if it didn't exist anymore.

And n-th order effects and externalities are specifically excluded from corporate accounting.

Which means we don't know how much these things actually cost in real terms. We also don't know how to quantify potential benefits.

(And if someone says 'Well, that's subjective' - so is nominal market value.)

There's conventional profit-loss accounting, and there's everything else. It seems the everything else can accumulate to ecosystem-threatening levels, and conventional accounting will continue to pretend this is financially irrelevant.