How many times will the US get deeply involved there, help throw the country into chaos, and then just walk away?

The US gives $2 billion a year to Egypt and $3 billion a year (actually much more) to Israel. The US budget is something like $2 trillion. Isn't rebuilding Afghanistan to the point where it doesn't fall into chaos again and threaten the world as a result worth as much as helping Egypt and Israel remain at peace?