I think it's entirely possible. Israel is in a pretty unenviable geographic position, entirely surrounded by countries which are at best neutral towards it, at worst openly hostile. Their population base is very low compared to these neighbours, and they don't have a substantial industrial base.
If the USA reduced or ended the aid they give Israel, it could well slide into a position of not being able to survive financially. Once that happened gradual absorption of its territories by its neighbouring countries would probably only be a matter of time.
Here's some info from the CIA website: note the parts marked *** :-
Israel has a technologically advanced market economy. It depends on imports of crude oil, grains, raw materials, and military equipment. Despite limited natural resources, Israel has intensively developed its agricultural and industrial sectors over the past 20 years. Cut diamonds, high-technology equipment, and agricultural products (fruits and vegetables) are the leading exports.
***Israel usually posts sizable trade deficits, which are covered by large transfer payments from abroad and by foreign loans.
***Roughly half of the government's external debt is owed to the US, its major source of economic and military aid.
Israel's GDP, after contracting slightly in 2001 and 2002 due to the Palestinian conflict and troubles in the high-technology sector, grew about 5% per year from 2003-07. The global financial crisis of 2008-09 spurred a brief recession in Israel, but the country entered the crisis with solid fundamentals - following years of prudent fiscal policy and a series of liberalizing reforms - and a resilient banking sector, and the economy has rebounded quickly. Following GDP growth of 4% in 2008, Israel's GDP contracted 0.3% in 2009 but is expected to expand in 2010. The global economic downturn affected Israel's economy primarily through reduced demand for Israel's exports - which account for about 45% of the country's GDP - in the United States and EU, Israel's top trading partners. The Israeli Government responded to the recession by implementing a fiscal stimulus package and an aggressive expansionary monetary policy - including cutting interest rates to record lows, purchasing government bonds, and intervening in the foreign currency market.