Except that in the case of your example Vietnam, like Thailand, Malaysia Cambodia, they no longer require vaccination documents or test results either according to the IATA COVID travel information page.
Having money in an account is not the issue for me and for a lot of people who do multi entry visas as opposed to visa extensions in country, the issue is internal Thai immigration's propensity to abuse applicants and it doesn't end until you get out of the loop of going in and paying tribute to your abusers once every 90 days and once a year for the big trauma fest of the visa extension circus. Its not really my thing.
If a Thai consulate in Vietnam or any of those other countries offers a multiple entry 1 year visa, that might be the way to go, but last I checked, Savanakhet is one of the few consulates that offer 1 year, non-immigrant O visas. I picked one up in Jakarta once, 10 years ago, great embassy, no queues, non-plussed, friendly, informed, willing to help, fluent, English speaking Indonesians working the windows, very nice, everything as it should be, though you do wait a week to get your visa. You can take some side trips around Java while you wait I suppose. But of course Indonesia is still like Laos requiring documents if they allow people at all into the country, though I think Bali is admitting people with just proof of negative testing results and they were offering multi-one year visas at an official franchise office awhile ago. That would really be the way to go I suppose, hang out at the beach for a week while you wait.
I don't see that there would be a big problem or a huge risk. Not having such documents when required, the airlines would probably just knock you back and you wouldn't be allowed on the flight or if they let you on the flight anyway, without test results, you might get tested on arrival in Laos or wherever. If you mean that upon being spot checked you'd end up testing positive and have to be sent to quarenteen, OK, I suppose for many people that would be a bit of a problem should the quarenteen be for a long time or even worse they just never let you out for whatever reason, such as being able to charge you lots of money for the use of the quarenteen facilities. But you face the same problem, going to a hospital to get tested, you test positive and I believe they take you away to the camp for a spell.
Also the situation as far as land entry versus air travel, is often different which is why I asked. I'm not flying to Laos, I'm travelling by land. So, I'm not really that bothered if I get to Laos and the immigration guy is in a bad mood and asks for my COVID documents and i don't have them. I'll just take the bus back into Thailand, get tested and get my documents and try again.
Thanks everyone else, sounds like good news, land crossing into Laos they likely won't ask for COVID documents. Hopefully Laos will soon drop their requirements as more and more countries do the same.