Thailand will probably stick with mask wearing the longest. Japan used to be known as the land of masks pre-Covid, not so much because everyone wore them (they didn't) but because the percentage of the population that would wear them for whatever reason, was higher than anywhere else in the world. You could easily find 1 in 10 commuters on the subway in Tokyo wearing them, especially during the winter months when people had colds.
That has now probably shifted to Thailand, mainly because the Japanese government has ended outdoor mandates and there is an ever so slight rebelious spirit among some people in Japan, which doesn't seem to exist in Thailand. Despite Japan being a more conformist society in general, during Covid, no country has been as conformist as Thailand, which is puzzling because Thais don't follow road rules or any other rules really. Only Covid.
Let's see what they decide at Friday's CCSA meeting, but I wouldn't be surprised if they don't budge on easing the outdoor mask mandate, not even a bit. They've been boasting they will end the practice at some outdoor venues/settings since December 21 (look up the Thai PBS article on the issue) and it has come up again and again especially recently, but the government refuses to budge.
I think they want to get some kind of award or something.
Some really brainwashed Thais who believe anything they're told on TV still argue on YT channels that the reason for Thailand's "low case count" is the widespread wearing of masks. Yet Thailand is now 24th in the world, with the 9th or 10th highest daily case count for several weeks running and is once again number one in ASEAN for the better part of a month now, having unseated Vietnam, which was number one and had up to 10 times as many daily cases as Thailand around 2-3 months ago.
Sweden's case count is significantly lower than Thailand's and that's the poster child country for not wearing masks practically at all throughout this crisis.
I think it must have gone down a lot because last year and probably up until January/February this year, it was widely complied with. Last year some foreigners were deported for not wearing masks in Bali, while others were simply made to do push-ups.
Like Phuket and Phangan, which were strict (especially Phuket) from the beginning up until around December of last year or January of this year, as of right now, mask wearing outdoors has significantly declined while I understand that on Phangan even indoor mask wearing is rare. This, despite the mandate in Thailand not having been lifted yet.