Can a U.S. citizen apply for a Non-OA visa while holding a valid extension and how many Non-OA visas can one obtain over time?

QUESTIONS ON DITCHING EXTENSIONS AND GOING WITH NON-OA VISAS.

U.S. citizen, extensions based on retirement (4), income affadavit method, Chang Wattana. OK guys and gals, it is getting ridiculous the continual changes regarding Immigration's requirements for funds to renew extensions based on retirement.

Income affadavit method goes away, alright, I will plan to proceed with depositing and seasoning 800K baht for the next extension late in '19. But now, with the word yesterday, a total five months of parking the funds account, and including a period of three months after the extension renewal--a time frame for which I would want to withdraw some of those funds for living expenses--is a very sour development. As is the new requirement to maintain a balance of 400K baht on deposit at all times.

If I'm reading all this correctly and that is the case, then the Non-OA visa acquired in one's home country is the way to go. Forget these required money amounts/seasoning requirements/after-renewal restriction on withdrawls and maintaining a minimum 400K baht in the account. So I would want to consider going that route.

Questions: Can a person holding a currently-valid extension return to their home country and apply for a Non-OA visa? Even if you have, say, six months validity left on an extension. Any experience with that?

Question: Is it possible over time to apply for a series of Non-OA visas, and basically reside here over the long term using them? In theory, because of the way the 'permission to stay' for that visa is structured, that would mean you would have to go back and acquire a new Non-OA visa once every two years. If you are someone who returns to their home country annually, as many do, that is not such an issue. Do the Thai embassy and consulates limit the number of Non-OA visas one can be granted? Or could one be granted the Non-OA visas in perpetuity?

Any first-hand experience or knowledge of what the answers are?