The larger impact could be a drastic reduction of foreign retirees locating in Thailand. The average Thai makes 10,000 to 12,000 THB, the average western retiree makes around 80,000THB. Which begs the question whose stimulating the local economy more?
Business leaders like to say investors are job creaters, however, nothing could be further from the truth. I've created 3 or 4 companies, but I've never actually created one single job. It was in fact my customers who created all the jobs.
Thailand would be wise to leave all these expats who are spending their money as consumers alone, and allow them to continue to create jobs for local Thai people.
Looks like the classic case of cutting one's nose off to spite their own face.