But a tax treaty doesn't possibly help in the fact Thailand tax brackets are very high as @HolyCowCm has pointed out.
So even though you pay taxes in the US on your income, you may owe more taxes to Thailand because their tax brackets are much higher for lower income
Plus, there is the issue for US taxpayers of the foreign earned income credit of $120k as well the standard deduction of $12,950 for single filers, $25,900 for joint filers or $19,400 for heads of household
Which Thailand taxes a lot higher for those sums above
But as you and I have stated, it is common in most countries to tax that income, so people who got off pretty easy in the past may now have to make some tough decisions if this goes through against them.......
People were very lucky for a long time that Thailand wasn't taxing full time residents, I think it's a bit misplaced to call them "leeches" to now come up to the mostly standard of most countries when it is your home and you live there...............
The intent of the change in rules is in part to respond to EU and US demands to crack down on tax evasion through selection of lax jurisdictions. Thailand previously did not have the systems, nor agreements in place that would allow it to crack down on freeloaders. They are in place now and people who have evaded paying tax over the years will have to pay now. Those who have filed tax returns in countries with tax treaties with Thailand will be protected from double taxation on general income. All countries retain the right to levy surcharges/surtaxes on special items. For example, health or pharmacare surcharges.
I've never heard of a predatory attack, though. As with bears, the element of hunting humans is not there. Scavenger bites are known, in fact, well known. As are attacks leading to rare fatalities. But despite how common Ametican/Mississippi alligators are, often living in close proximity to man, they simply don't kill humans for food, as would a broad snouted crocodylid that size. In fact even big gators, only rarely prey on adult cervids and feral pigs, usually Odocoileus, a sort of roebuck analog native in North America.
The thing is that you choose to live in a high tax country and you may not want to hear this, but you have gotten away without paying taxes in Thailand that most countries would have made you pay.
You are sighting USA tax laws, but if the situation were reversed, the US would absolutely be taxing you up to the tax bracket there if you were living there, deriving income outside the US and not paying up to their tax bracket level.
As for taxing you on money brought in, I just don't think that will happen, Possibly may need to report your US accounts not, which is what the US does to their citizens(tax residents) that live overseas now