A regular income person is a millionaire in South Africa. It caused some problems.
"I agree with that [immigration is a net benefit to nearly everyone] and support more or less open borders" - yummyfajitas
Unfortunately most poor Americans refuse to work, commit disability fraud and otherwise exploit the taxpayer, and commit disproportionate amounts of crime. (Far more than Indians - I've never felt unsafe in any slum here, unlike in the US). You don't get any comparative advantage from people who refuse to trade and merely take things from you.
$30k for a family of 4 is $20 per person per day. That's 8 times more than $2.50, but the cost of living in CA is (probably?) approximately 8x the cost of living of Africa, rural India, China, etc (where these 3 billion people live.)
You can't do any of that in California, in any reliable way... and in many parts of the state, $30k/yr just isn't enough to rent an apartment and cover the basics (food, transport, medical care). So yes, the poor in the US are both better and worse off than poor in the developing world.
Pre-Katrina New Orleans was popular because survival was similarly cheap, not for the same quality of survival, but the bottom possible was lower.
Nevertheless, SF actually has pretty good services for the homeless. That's why there's a lot of homeless people there.
Given also that the median black household income in California is $35k, it sounds like you can actually survive of $30k in Cali without your kids dying of dysentery. Alternatively, if you want to 'scrounge crude shelter', there's 11 million square miles of public land in California.
In short, my eyes just about goggled out of my head when the response to "kids die from drinking dirty water" is "yeah, but they can live wherever they want".
Oh no, I can't afford beach front property or a mansion in Beverly Hills on $30K a year? Poverty!
http://www.apartmentcities.com/Los-Angeles-Apartments/Los-An...
15 pages under $500 in Los Angeles.
>and worse off than poor in the developing world.
So you won't mind moving there and living on a local salary, eh?
"poverty"
https://www.dosomething.org/us/facts/11-facts-about-global-p...
"more than 3 billion people — live on less than $2.50 a day."