Nobody can tell the future but I suspect Israelis will look back and wish they'd settled for the deal Shavit regards as impossible. And any interim deals are just rubbish that serve Israel's interests by avoiding the only fair deal. The pre-1967 borders ARE a huge concesison already from the Palsestinians.
Palestinians report IDF airstrikes on Islamic Jihad targets in southern Gaza Strip (Haaretz)
from the article: At the very least, a de facto two-state solution is needed