You are pointing out why the refugee crisis still exists after decades. No neighboring countries will accept the Palestinians, and many don’t want to leave.
Israel is clearly creating the problem, but other regional actors are using the Palestinians as pawns because they don’t like Israel (and don’t actually care about Palestinians dying). Larger countries like Saudi Arabia and Iran have the land and the money to give them a better life.
Iran especially doesn’t care about the Palestinians. They’re a different religion, as you can see in this picture: