Politicians promise what people want to hear.
They almost never point out the need for a coalition and compromise to get any where near what they promised. That would give them the look of lacking integrity. So words are spoken, with little or no evidence they have the will to do anything that will move their agenda forward, even if it means making concessions, not going for a pure end, and even being called a member of the other party.
The work is difficult and promises are easy.
Which is why they do what they do. Alas!