Gaza got billions of aid since 2005. Water pipes were built, material was delivered. What happened with it? They built one of the biggest underground tunnel systems in the world (as we can see right now), they dug out the pipes to use them for rockets, same with the material. And all the time they attacked Israel and then said "we cannot live in peace, Israel blockades us", leaving the 'after we attacked them again and again' part out.
Palestinians had all the help in the world to live a peaceful life in the Gaza strip with more freedoms over time if they can show that that freedoms don't lead to more dead Israelis. Each time they chose violence instead.