In the West, do most contemporary philosophy students and philosophers reads the entirety of Western philosopher?
Do they, for instance, read every single thing written by Hume, Voltaire, Nietzsche, Plato, Socrates, Aristotle, etc.? Or, do they read, say, the most relevant few pieces of each philosopher?
I ask this because while reading Hume and Russell, I found that they were calling upon an extraordinary deal of philosophers that I haven't even heard of, despite that I find myself reading philosophy every day. And their ability to cite very specific passages that were actually relevant and supporting of their argument, seemed extraordinary to me. They seemed to understand everything that was every written. I know this cannot be the case, but I'm wondering how far off I am.
As an example, let's take a famous contemporary philosopher like Daniel Dennett (although he is not famous for his academic philosophical works) -- would you suppose someone of this sort has read the entirety of Plato, Hume, Voltaire, Pascal, Locke, etc.?
Stated another way, has the average professor of philosophy, in any given university, read these sorts of thinkers in their entirety or just the most relevant works? (like Hume's Natural History of Religion; or Locke's Treatises of Government; or Plato's Apology and Republic)?