The occupation is a money maker for Israel.
This is because Israel has complete control over everything that goes in and out of the occupied territories and can, and does, tax them all.
In addition, because of the severe restrictions on imports, Palestinians are forced (except for items brought in through the Gaza tunnel system) to resort to Israeli products.
In the following segment of an episode of the Max Keiser Report, economist Shir Hever gives a fact filled account of the situation that is well worth hearing. Go to 12:45 in and watch to the end. Keiser gives Hever the floor almost without interruption - a we, the viewers, benefit.