If you "earn" less than THB 150,000 in a given year you don't have to pay income tax, and are exempt from filing a return. The company I worked for filed one for me in Bangkok every year I was working, but since retiring I changed my tax jurisdiction to my home province and visit them each year showing my bank statements for Thailand and the overseas account I transfer from. Each time I'm told I don't need to file a return. This includes a year that I was audited by the revenue department.
Staying below THB 150,000 has been easy to do under the current law, but may involve more effort / be impossible going forward, depending on how the new directive is implemented. The countless speculation on multiple threads is quite worthless until the full details are disclosed.