Yes of course Thailand doesn't offer expats of retirement status residence security more than a year at a time, but they do have a formal retirement visa and extension program, they aren't going to abolish that, and Vietnam never will have such a program. I oppose Vietnam being put on any best places to retire abroad lists but weirdly they still often are.
There are countries with not specifically retirement visa options that retirees can use to live there and even transition to permanent residence and citizenship. Those places are legit candidates for such lists.