Because no president will ever be concerned for all people of all classes and races, or indifferent to corporations and special interests. First, understand that a corporation is simply a group of people who have pooled their resources in order to do business. Second, a special interest is any group that sees itself as having a specific desire for a policy change. Everyone with a pulse is a special interest. Factionalism is part of human nature, and cannot be eliminated. The solution that the founders came up with was to use factionalism as one of the checks on power in the government. They set up the system so that anyone trying to game it for their own good would be in conflict with those who opposed that particular outcome, because it conflicted with their own good. That's not to say that the system was incapable of action, but only that actions which fundamentally altered the basic structure of the system would be difficult to implement. It took the Civil War, WWI, the Great Depression and the rise of a technocratic class of media and governing elites to impose those changes. The best that we can ask for from our government is its recognition that my personal problems are none of its business. A government that has the power to give me what it thinks I want also has the power to take away what it thinks I shouldn't have.
We would get leaders more concerned about the general people if we stopped allowing corporations and special interest groups to buy elections. Okay, I know every bone in your body might be against this, but think about it. Every election, at least one candidate is being purchased by NOW, EPA, unions, etc. What if the rules changed so they couldn't do that anymore? We could both get something out of that.
The left is not a place where you arrive and just stay contented, you are never left enough, there is always another level of idiocy you must achhieve until you either burn out or destroy everything in your power, you are never truly left, just on the way there.
I often feel like it's never enough for far righties. Are they just RINOS?