Have you been to Thailand recently? Lower Sukhumvit is full of head shops. The “old laws” meant prison or worse for anyone selling it. There is indeed a new ban being suggested, to take place in 2025:
https://www.euronews.com/travel/2024/07/09/is-weed-still-leg...
Outside of the tourist/expat/backpacker bubble Thailand is very conservative.
Neighboring Myanmar having Balkanized into multiple mini-narco states doesn't help either.