The USA is hugely subsidizing Israel. Israel would not just get a little poorer if the USA quit. Israel would go down the tubes (short of a divine miracle).
Aid to Israel is 4 billion a year. Israeli GDP in 2002 was 122 billion. Israel wouldn't fold if it lost the 4 billion. I'm not saying we should quit giving it... rather, that it's not sink-or-swim for them. They have a vibrant economy that produces a lot of high-tech innovation, unlike the Egyptians (for example) who would probably suffer instant chaos if the US aid were withdrawn.