The biggest aid contributors to Gaza are the EU and the US, not other countries in the Middle East (the Saudis especially do send aid, but it's significantly less than a billion per annum.) Sure, Hamas pulls in several hundred million dollars per year and I'm sure some of that is military spending. But when you combine the annual U.S. budget for DoD and DHS, it's a little under $1 trillion. Ever thought about running a long-term war on a budget of a percentage of several hundred million dollars? The Joint Chiefs of Staff would laugh you out of the room!