In 2020, Duiran prices in Thailand fell dramatically. Covid-19 travel restrictions meant they could not sell them to the largest market - China - and so there was so much Durian going un-sold that some people were giving them away for free.
Covid completely screwed up the market this year as well. Paying less than $1/kg (full fruit) wasn’t rare while normally years it can be several times that.
What are you talking about? There’s no durian that goes for 30 baht/kg. Only in Phuket I see the local variety at 50 baht but monthong is still 100/120 now. In Bangkok it’s rare/impossible to find it for less than 140.
Probably that price is only found near the plantations and very likely not for monthong.
I know because I eat a durian a week and I’m stingy.