It is easy for immigration to require a tax ID for all 90 day renewals.
Once they have your tax Id they will monitor your Thailand bank accounts and your tax returns or lack thereof, and flag you at your next 90 day immigration appointment if they think something is fishy with your tax filings.
🍺 🍿
If the tax laws change to include a new taxation of an expats non-Thai/worldwide income, regardless of if/when it is remitted, you will indeed begin to see a very serious “mass exodus of quality expats” from all over Thailand.
Yes it is a big island and offers something for everyone.
East coast property is much cheaper and far less visited for many reasons.
Enjoy the east coast if thats your thing, but most people understandably prefer the great beaches and amazing sunsets on the west coast.