There are few statements you could make about philosophy emptier than to say it's a history of mistakes. Likewise there are few moves you could make in the game of "doing philosophy" that are emptier than showing that a philosopher was wrong about something. Around 100% of philosophical ideas are completely absurd. Plato really seemed to recognize this, too. Of course there's pathos and tragedy in Plato, too. Hard to avoid considering they killed his teacher. But there's no doubt Plato considered himself a self-parody much of the time. Nietzsche would have been as funny as Plato if he weren't German.
The more challenging and interesting task is to figure out why an absurd philosophical view was so tempting at the time. If you asked a person completely uneducated in philosophy to cook up the most ridiculous idea about the world he possibly could, he wouldn't even come close to something as ridiculous as, for example, Berkeley's doctrine about ideas. It's as though philosophers (at least the good ones) are gifted with something like superhuman powers of absurdity. Plato double-underlines this when he places the philosophers in charge in Republic. As if he's saying to Aristophanes, "Oh, you thought philosophy was crazy before. Just wait until you see THIS!" Plato illustrates this through wacky conceits, like treating the sexes as equals. A modern-day equivalent would be a republic wherein the primary means by which people transport themselves from one point to another is using coal-powered pogo-sticks. To say (with Hegel) that the philosophical view of the world is "inverted" is to put it lightly.
Suffice it to say, no one should get a gold star for pointing out that a philosopher was wrong or that the history of philosophy is a history of mistakes. The real question is: Is it a history of mere mistakes? Or is there something else going on?
My own view is that the history of philosophy is the development in thought of consciousness itself, or transcendence in general. But this development in thought is largely the byproduct of technological advance. (I think technological advance is foundational with respect to scientific advance.) This has led to a purification of subjectivity which can be seen in Husserl's transcendental phenomenology (and all its off-shoots) as well as in the precise formulation of the hard problem of consciousness. Naturally this is not all there is to philosophy. There are also questions of ethics. But ethics belongs to transcendence in its own way insofar as ethics always goes beyond the way the world is and into the way it is not but ought to be.
But as then, so now. Philosophy is not going to solve these problems. It can't. It can only pose the questions. The problem will be solved when the question is ignored and a new one put in its place. That's what all really good philosophers do. They change the subject. We're dealing with the current set of questions because of the current state and trajectory of technology, especially information technology. But with change in the material basis of society will come entirely new possibilities of thinking about transcendence. The best philosophers of the future will be the ones who come up with the most brilliant and novel errors.