I spend money here, I just don't do remittances. I don't have nor have ever had a Thai bank account.
I'm from an Asian country, so my country apps support the thai QR system here. I can pay any QR code directly with my home country accounts. I pay everything this way, including rent. In case I need cash, I can also withdraw cash from the "purple bank" (is it SCB?), thru my home country bank app, no need to pay the 250 baht fee, either.
Also I have TrueMoney, which allows me to transfer to regular Thai bank accounts, if I need to pay something.
About taxes? I don't know / don't care. I don't remit any money here.
About staying throughout the year: I was here even before Jan 1st. and am still here, so it's possible. I've traveled here and then during the year to visit home, some 10 times or so, but always stays of a few days.