Most of the damage had already been done by mid-March, at which stage people were still largely ignorant about the effects of the virus and how rapidly it spread. The climate obviously has quite a big part in the huge disparity of cases and deaths when compared to Thailand, but no doubt the Thai government have opted for more of a be all and end all approcahc to the virus whilst not considering the huge ramifications it will have for the future of the economy - which, let's face it, will be totally and uttrely fucked. The knock-on from that will be abject poverty which may lead to more death and a soaring crime rate, more than any virus could cause.
Just saying that at present the UK are playing the game, wearing masks and generally 'staying alert' as Boris would have it.