If I were a rich foreigner looking for a place to retire, La Jolla would not be near the top of my list.
In Brazil, that kind of money buys you a 10,000 sq ft beachfront mansion, or a huge ranch with orange and banana plantations, and you’ll save enough cash to hire a bunch of servants for life to take care of your property. (Their minimum wage is $200 a month and many people don’t make even that)
Visa problem is an even bigger one. You can’t just buy a house and move here. The whole immigration system is set up to make sure people DON’T do that. With the exception of Canadians, almost any foreigner who intends to stay in the country for more than 90 days needs to get a visa. There are two kinds of visas – immigration and non-immigration. To get an immigration visa, you need to have relatives here, find a good job in the States (H1B process), marry a U.S. citizen, or invest $1,000,000 into the U.S. economy. (Buying a house does not qualify.) Non-immigration visas are given to tourists and U.S. embassy is free to deny a tourist visa to anyone. In fact, owning a house in the States is an indication of immigration intentions and that alone is grounds for automatic denial of a tourist visa.
Would you want to spend 2+ million dollars on a house if you knew that you had no legal right to stay in the country and its government could prevent you from coming back if you left?