The Thai government are very very risk averse, due to the C-Word, & have pretty much kept all borders closed since March. They are totally paranoid about "letting Covid-19 in" from abroad...rightly or wrongly.
Here in Phuket its (relative) bliss for us without thousands of tourists BUT the economy is hurting very badly.
I suspect tourists will be allowed in to Thailand this year (they NEED them) but under strict conditions only. Watch that space.