Concrete can be (and has obviously been) used to build infiltration tunnels under the border. If the Gazans were not building tunnels, and in general were not engaged in provocative acts such as firing rockets across the border, there's no limit to the trade and investment that could be happening between the two regions. The sea coast could be a billion dollar resort; the Gazan labor force could be productively employed; and the farms and greenhouses could be growing tons of items for consumption and export.

This woman's enterprise, established under the sparsest of conditions, is an example of what can be done if there were peaceful relations and if the government in Gaza were truly representative and dedicated to peaceful negotiations etc. A warlike government that caters to the militants in Hamas, Al Aqsa Martyrs, etc., is simply uninterested in economic development, nor does it have any native expertise in that area. Its only legitimacy is based on armed conflict with its neighbor and armed suppression of dissidents internally.