Just got the "official" word today from my embassy:

New Health Insurance Requirement for Long-Stay Visa Applicants (November 8, 2019)
Location: Thailand
Event: As of October 31, 2019, Thailand requires all long-stay (O-A and O-X) visa applicants to carry health insurance. Per Royal Thai Police Order Number 548/2562 dated September 27, 2019, foreign nationals who have been granted a nonimmigrant O-A or O-X visa must purchase health insurance which covers their length of stay in the Kingdom of Thailand. The coverage must be no less than 400,000 Thai Baht per policy year for inpatient care and not less than 40,000 Thai Baht per policy year for outpatient services.
U.S. citizens can present proof of existing insurance (U.S.-based or otherwise) that covers them in Thailand or they can purchase an insurance policy via the Thai General Insurance Association’s website at http://longstay.tgia.org.
U.S. citizens will need to download the Overseas Insurance Certificate and have it completed, signed, and stamped by their insurance company if using a non-Thai insurance policy to qualify.

Checking out many of the companies offering the minimum insurance for a person of my age (67) looks like annual cost will be around US$ 2,000.

Couple of questions for anyone who might know with some certainty:

I just got my O-A visa extended for another year (my sixth annual extension) and it's good through September of 2020. The language above seems to be internally contradictory. The first sentence says "...Thailand requires all long-stay...visa applicants to carry health insurance.) The second sentence says that according to the Royal Thai Police order..."foreign nationals who have been granted a nonimmigrant O-A or O-X visa must purchase health insurance..."

QUESTION ONE: Which language is correct? Since I am no longer technically an "applicant" and already have the visa for another year, do I still need to purchase the insurance?

QUESTION TWO: I'm taking a short trip in Korea right now. When I return to DMK airport in three weeks, will entry be denied without an insurance certificate?

QUESTION THREE: As the insurance requirement does not seem to apply to tourists, irrespective of the answer to Question Two (above) would I be granted entry in three weeks as an American tourist for 30 days, even if I were denied entry for lack of an insurance certificate?

QUESTION FOUR: Tourism sinking. National airline on the verge of bankruptcy. Still no reliable signs of a return to Democracy. W.T. F-ing. F?