Thais are very status conscious and western relaxed attitudes to this have a huge bearing on how they are treated in professional settings.
I opened an account on a DTV when people were already saying they were no longer available.. I have opened accounts on no visa at all.. I obtained a bank safe deposit when others were told there was an (infinite) waiting list.
You need to know how to play the game here, the rules are not the same as elsewhere.
Said it many times.. Bank branches make their own policy (some like bangkok being harder than others) and if they judge you worthy, you can obtain a bank on any visa class.
Thais judge very firmly on appearance.. Dress business casual, shoes / watch / folio, be well groomed.. Dont wander in wearing sandals and jeans or worse shorts and a rumpled T shirt.
Its also new information that those who opened on other visa classes will have accounts closed after they find out you are on a DTV. We know other banks close and KBank once again showing a little more class about it, giving a period to change.
Its happened 4 or 5 times to a friend on a long term non imm O and work permit.. So dont assume because it has happened its the end, the whole system is a mess.