Then again, if measured purely from the East German standpoint, the Berlin Wall _worked_ - it stopped mass emigration to the West. It fell when the political system that supported it fell. If the I-P conflict ever reaches a negotiated settlement, the West Bank wall might also fall.
Your point about an economic solution can't be denied. I also think that a Palestinian state - even an interim one - will have to be viable, with sufficient infrastructure and trade outlets to allow an economic life. You may be interested in what I've written on water infrastructure in Gaza:
The thing is that for any of this to happen, Israel has to get the hell out first, and the wall is both a real defense and an important psychological factor that will enable withdrawal. I'm not thrilled about the wall - no sane person would be thrilled about the need for such measures - but I think it will ultimately do more good than harm. A period of separation is
necessary before there can be peace, and a physical barrier like the wall(preferably built along the green line) is the only thing that can provide this.
We basically agree that the wall is needed, but my German side still has a phobia of them. Discussion of the Berlin Wall was a regular topic at the dinner table when I was growing up. I would like to see a political and economic solution without the wall, but in lieu of some sort of demilitarized zone with some sort of foreign force separating Israelis and Palestinians, it's the next best thing. But you know what, if they manage to work a peace, I don't care how they do it at this point. The Israeli-Palestinian conflict is the seed of modern terrorism and we will not get a handle on the problem unless we have peace in the Holy Land. The infrastructure of the Palestinian lands has to be rebuilt and that will only come with investment, and there will be no investment until there is peace.