I feel for you as Thailand is not always easy. Unfortunately you do not state why the banks have declined, is it your residence status, cash or whatever, surely you were advised why they could not open for you. If not satisfied ask to speak to the manager. Most banks have a list of requirements which they give to you.
Far to often people complain without following simple steps, they get angry which is a no no, and your post appears to show that.
Have your wife talk in Thai requesting exactly what they want from you.
so you have a good background and opportunity, however you need an offer and work permit first.
A lot depends on where you wish to live. A rural or semi rural is very cheap, but life is not easy for us. Major cities like anywhere have huge cost differences.ie. Pattaya is cheaper than Hua in, phuket and Samui, even much of BKK