You claim was: "As a foreigner, the words "Thailand" and "investing" should not be used in the same sentence."
I have a wife and son in Thailand, and even if I did not, any investment I might have here could be liquidated in the event I wanted to leave. I am not worried about my visa, If I lose it, I'll move back to the states. There are still plenty of nice places to live there.
Most of your reasoning makes little sense. What does having to fly home for medical care have to do with anything investment wise?
I invest in international funds that include any number of countries where I would "...have no "right" to permanently live in the country.", does that make international funds a bad investment? Silly.
That the bank in Thailand pays less in interest than the bank in your home country, or that capital gains on real property in your county is better than in Thailand may make investing there a better idea for you than storing cash or buying real estate in Thailand, but it does not make investing in Thailand the terrible risk you want to make it out to be.
Much of what you say I agree with. My brokerage account is in the US as is most of my cash. I am not advocating investing in Thailand, but I think claiming/implying one would be a fool to invest here or keep money here is wrongheaded.
We live in a building that's worth about 150% of what we paid for it about ten years ago. Over that same ten years, my US investments have more than tripled, but that does not make our home a bad investment any more than drawing 4-5% in my US bank (now) make the 1.5-3% we draw in the Thai bank a bad investment.
Incidentally, I seem to recall that the Thai banks were paying much better interest than were the US banks not that long ago.