Official guidelines stated on Thai immigration websites are that onward ticket is required.
Many consulates will reject you if you dont have it.
Also, even with a visa approved and in your passport, immigration may reject you on entry if you don't have it.
In July, I was pulled aside at the airport and asked to show proof of finances, onward ticket, and accommodation - which I'd already submitted in Kuala Lumpur to get the visa in the first place.
Like, "Yeah, I was totally gonna overstay my visa, and live & work in TH illegally, but they're making me show proof of a 3,000 Baht flight to Laos so I guess I'm not gonna do that anymore".
Its relevant to the discussion because the argument is that Thailand needs the foreign cash that tourists and expats both bring into the country in different ways.
The country needs said cash, because the state is in a financial hole.
One of the factors behind said financial hole is the poor decision making by several governments - like spending tens of billions of Baht it could not afford on submarines which are basically useless for their intended purpose.
A country like the US, or China, can afford things like aircraft carriers, submarines etc (albeit at the cost of things like providing healthcare & welfare to its own citizens). Such countries also have the resources to maintain & use them to project power, to the point that acquiring them at least makes some semblance of sense.
Neither of those things apply to Thailand, which, in the case of the Chakri Narubet aircraft carrier, spent 6 billion Baht they didn't have, on an item that they got basically no strategic advantage from.
Also, the incoming Pheu Thai government is proposing giving every citizen 10,000 Baht.
That money is going to have to come from somewhere
Rude and entitled farangs annoy everyone here, including most farangs.
But we had a glimpse of how Thailand fares without foreign money/tourism over Covid, and it was economic devastation, people losing everything, suicides through the roof, homelessness rising, etc, etc.
Plus, on an economic level, the government needs the revenues more than ever before, as they're flat broke, having had to borrow a ton of money during Covid, and having squandered tens of billions of Baht on purchasing submarines from China.
Submarines which cannot be used in the Gulf of Thailand due to being completely the wrong type of draft - though they do fit rather nicely with their 6.1 Billion Baht aircraft carrier; the smallest in the world - which now sits at harbour as little more than a museum piece, is barely seaworthy, and doesn't even have any launchable aircraft.
Not to mention the fact that the richest people in the country are flat-out exempt from taxation.
One small issue - if you have two back-to-back visa exemptions and extensions in your passport, and then decide to go out and get a visa, you may well be pulled aside at immigration and questioned when you try to re-enter.
This happened to me at CNX airport a month ago, even though I already had the visa approved - and I was asked to show my bank balance, onward flight ticket and hotel booking; the same documents I'd already had to show in Kuala Lumpur to get the visa in the first place.
Thats true *if* you surrender at immigration at an airport (and the overstay is under 90 days).
However, if you are arrested or questioned by officials, and it is discovered that you are on an overstay of *any* length, then you can and will face a 5 year blacklist.
Usually this applied only to people arrested for, say, some stupid drunk shit.
However, there have been people subjected to spot checks (on Samui, for example), and then getting a ban for just a 1 day overstay.