There are only two categories of DTV, Soft Power and Workaytion. Retirement is not a category that qualifies for a DTV. There are other visa types for that - 4 I know of the top of my head "O", O-A". "O-X" and "LTR".
There were other individual branches at other banks. For example Krungsri at EmQuatrtier was well known for facilitating account opening on VE and TR. It was individual branches of banks though - pretty sure it was down to the discretion of the manager. Many could not be arsed 🙂
Who issued the rule? It was never a "Law". Was it a BoT (Bank of Thailand) rule or guideline - must be a link to it. Was it a rule of individual banks or was it just left to the discretion of individual bank managers?
Sounds to me the agency is trying to maximise income by offering the ED rather than the DTV. This type of marketing is called FUD (Fear, Uncertainty & Doubt). The new government will not be making any changes in the 4 months they have before a General Election next year. There has been nothing said by anyone as far as I can see regarding the DTV by any political party. It is not exactly an everyday concern to the electorate. Apply for your DTV and good luck. Edit: the ED is recurring revenue for the agent. The DTV is a one off payment for them.