BTW. Follow the logic of your own situation. You have been in Thailand for a year. You can't work as a tourist and you don't have enough money in the bank to last more than a couple of days or a week. That doesn't look suspicious?
Personally, I think there should be an option for people under 50 to stay here longer term. Also . . . there is a 6 month multiple entry tourist visa available. That might have been a better place to start.
Both the Consulates and the border immigration officers have the discretion to deny you entry. They are particularly suspicious if they suspect you are in Thailand working.
As an American you should be familiar with US Immigration having a harsh standard of letting foreigners from many countries entering the US. It is extremely difficult for many Thais to get a visa to enter the US. Consider it reciprocity.
Note that a 90-day report is something you do when you are in Thailand 90 continuous days. If you leave and re-enter before 90 days then 90 day clock resets to day 1.
Just keep trying. There are years of reports of people obtaining Thai bank accounts on short term visas. My friend said he came here on a short term visa and tried at a dozen banks before being able to open an account. Anecdotes like this abound. I almost got rejected even though I had a fresh O-A visa. My girlfriend intervened to convince them to give me the account.
Jonathan Pressburger They are probably not looking at the details at all. I wonder if two deposits would be ok if you could back them up with proof such as a pension statement and Social Security statement.