It’s not a presupposition when Palestinians are pretty up front about wanting exactly that. A single state where only one religion has full rights is the most popular solution among both Israelis and Palestinians because both groups have genocidal actors who aren’t shy at all about what they want to do to the other side. Palestinians need self governance, Israelis need security.
Yes because Israel has never really made a fair deal. There have always been caveats or deceptive land swaps. I.e. Israel gives up 20% of the West Bank for 10% of land somewhere else, but all that land in the West Bank is literally rocky hillside. Most of the Israeli governments that have been part of negotiations were not really acting sincerely. The most recent time there were serious, productive talks going on, the Israeli PM, Yitzhak Rabin was murdered by a Jewish extremist. He was replaced