traveller wrote:So in other words, is the USA really the only country worldwide that has some sort of government-provided income, such as SSI, for people with disabilities, especially those who can not work?
No, most Western countries have it, including most of Europe, especially countries like Sweden, Finland, and Denmark. Countries that are "third world" generally have very minimal/no social safety nets, though. However for immigration, you cannot get permanent residence without a job in basically any country. This is the same for USA, they won't let you legally immigrate to USA unless you're working at some place, somehow. They figure their own citizens are enough drain on their welfare system, and do not want someone immigrating to drain their welfare, too.
Now, once you're in the country and attempted working, and have permanent residency status, then you're usually
eligible for welfare benefits in that country like the actual citizens of that country (though sometimes not.) For example, I looked up Switzerland now, and you can receive their SSI if you've been a permanent resident and contributed to the system for 2 years. But you cannot go in claiming disability and just get benefits once you've hopped off the plane. Other options as well include say the rest of your family wanted to move to a country, and they were working, and you were not and were disabled, then usually you'd get benefits as well or at least the ability to legally be in the country (though again, maybe not) just because they'd be more understanding of wanting a whole family living together and wouldn't be heartless enough to separate a brother or sister or father, etc.
Of course too, there are some countries like UK that are very liberal with their social benefits, and people fresh off the boat from other countries (usually within EU) get benefits instantly and this is a scandal across Europe, and I don't know how they're managing to do that and how that works, but how I said with at least attempting to work is how it is normally for most countries.
Now, I don't know the extent of your autism and it's effects, but it's my belief in another country I may find working much easier with my Aspergers (and I'm probably able to get SSI for it too if I tried enough) less need to drive places, less need for social subtleties, etc. So it depends on how you are. But even without working in another country, if you do have the ability to save money here, it doesn't preclude a 90 day tourist visa, or even sometimes a 6 months or a year or more student visa, stay renting a cheap apartment in the country you choose, which even though it's not full immigration, is still better than most of the people on this forum who go "man I showed up to the Philippines for a week and half and went to a whorehouse, happier abroad 4 lyfe!111" Then on that 90 days in another country, who knows, maybe someone will offer you a job? Maybe you'll meet a girl? You won't know until you try. But as another poster said, if you look for excuses like property tax to not go to a country, then nothing will happen and your life will remain the same as it is now here.