People here are all saying rich or trustfund or something. But in my experience people who do that are often still young and living with their parents, which allows them to save a lot of money and have no rent to pay.

And where I'm from many of them travel to backpack countries like Thailand or Indonesia. Plane tickets to those countries are not cheap but once you're there you can live really cheap if you want to. You can get pretty decent hotels for 10-20 euros a night in those countries (can be even cheaper if you're willing to sleep in hostels. And food and activities can also be really cheap. So if you save up a couple thousand bucks you can live/travel in these kinds of countries for quite a while.

Do you mean that their API's are similar or the same? That's why they can interconnect?