Yes, can be scary. Would be nice if the DLT posted actual Thai regulations concerning this issue, duration of IDL/IDP use, otherwise open to debate/interpretation, misinformation, which could impact someone severely. I don't know anyone specifically ticketed for not having a Thai driver's license while having a valid IDL but don't know about insurance coverage, which would be the greater concern.
What would seem to resolve this debate is ACTUAL experiences of people on their IDP/IDL and accident insurance coverage. Also, has anyone been ticketed by police for driving over 90 days on a valid IDL/IDP? Jim Howard stated that he was hospitalized after an accident and was covered (Thai or foreign insurance not stated). Was anyone denied a claim for accident insurance while using only an IDL/IDP after 90 days? Anyone else who was covered by accident insurance after 90 days using an IDP/IDL? Jim Howard has shown the Roads Act and the approval of use of an IDP/IPL, with no time limit mentioned. Others have linked insurance websites with a different 90-day interpretation. How about if you have overseas insurance without this requirement? Anyway, actual tickets/claim experiences would tell us how it really works here.
Point being, thousands of foreigners are building houses in Thailand that have familes here. Their investment in a family home makes great sense, counter to your point of not investing here. Single, I would not invest (for profit), with a family, so many other factors are involved. Making a general statement of not to invest in Thailand is, at best, misguided advice.
You obviously don't know the property market on the islands then, and nothing of land sales. I'm retired, my wife is a part-time agent. Bought plots of land here a few years ago, subdivided and made millions in that short period. I'm not talking about condos in BKK. Smart investments are great...and if you have a family, and want to leave them with something when you pass, a property investment is a very, very, smart idea. You sound woefully uninformed.
Do you understand the property market here? My wife has bought and sold land here for the past three years and has made millions. Great investment opportunities here. And for my family, I spent 7M baht for land and house, equilvalent rental at least 70K/month (4 bedroom with pool). Over say 30 years, my rent alone would be 25M and myt familyt would have nothing. Instead, whenever I pass, my wife and kids have a free house for a couple decades (or rent the house out). At that point the land would likely be worth more than the house. Sorry, investing in property here makes much more sense if you have a family here. No brainer.
I live on Samui, and although rarely visit a hospital, there are 4-5 private hospitals here and a new one even opened last year (also have the typical government hospital). As far as the crowds/tourists, need to head south to get away from all that. The entire bottom half of Samui has dozens of quiet villages, coconut groves, mountain retreats, with few people and no traffic, yet "the action": is 20-30 minutes away. Fortunately, most people, and tourists, stay in the North and Northeast. Hope it stays that way for another couple decades.