sorry but you're the one who is "completely wrong." The non immigrant O-X is a ten year visa. Much older than the new LTR. And how could anyone possibly know if Vietnam's 10 year visa is better if the requirements and benefits haven't been announced yet?
you don't get six months in europe. Some countries get 90 days and you can do that twice a year, 90 days apart (actually 90 days within each 180 day period). it's not that different. There's no fixed number of times you can do the 60 days visa exempt (30+30) in Thailand. Moreover, ascribing any particular strategies to visa regulations here is about as accurate as astrology. Immigration moves in mysterious ways