This is precisely the dilemma faced by all governments, even juntas, not just in terms of tourism (which of course is the main earner in Thailand), but the economy as a whole. You're a bit 'damned if you do, damned if you don't'. It's a balancing act. Democratic governments also have to think about the next election, not something juntas have to worry about.
The UK appears to have gone for broke; get as many people vaccinated as possible, and as quickly as possible. To all intents and purposes, internally (i.e. excluding arrivals from abroad) we are on the way to getting back to normal as regards lockdowns and restrictions, although there are some differences in approach between the UK's countries.
People are holidaying abroad, though obviously not in pre-Covid numbers, a new word, 'staycationing*' has entered the language for holidays within the UK, crowds are back at sports events (and although that might not seem a priority, I can't begin to describe what a difference it makes), pubs are open. Obviously things are far from perfect, but it seems to me that there is a general feeling of optimism. Of course, the test will come in the next few months as the weather gets colder combined with possible new variants...
But my point is that everything is dependent on vaccinations. I don't see how anything can be done until that has been completed, and Thailand is way, way behind.
*Actually, staycationing seems to have been around since 1944, but it's new to me...
