Was the Latter Half of the 20th Century a Golden Age for Philosophy?
No, you will say. And I tend to agree, probably not. But let me make the case against dismissing the idea out of hand.
One framing thought is this. The normal condition of humanities research in academia is probably to be poorly funded. People on the left would rather fund poverty relief. People on the right would rather not fund at all. Pragmatists in the center want to fund disciplines with what is perceived as "practical application". The normal condition of humanities research in academia is probably also to survive as a conspiracy of mediocrity in which social connections and political alliances determine position much more than research quality does. Anglophone academic philosophy has, perhaps, defied gravity for a long while already.
Another framing thought is this. Greatness is comparative. In an era with lots of philosophers not vastly different in quality or influence, in the eyes of their contemporaries, it might be hard to pick out a few as giants of world-historical stature. But with time, with the winnowing of greats, that is, with the forgetting of almost-great philosophers, those whose works are still discussed might come to seem more nearly peerless.
I'm considering a fifty-year period, 1950-1999. Ancient Greece hosted a golden age in philosophy, but if limit ourselves to a comparable fifty-year period we probably can't include all three of Socrates, Plato, and Aristotle at the height of their powers, instead having to settle for two plus their lesser contemporaries. The early modern period in Western Europe was probably also a golden age, but again a fifty-year restriction limits those who can be included. By aiming very carefully we can include Descartes' Meditations (1641) through Locke's Essay and Treatises (1689-1690), plus Spinoza and Hobbes in the middle and a dash of Leibniz; or we can run from Locke through early Hume, with most of Leibniz and Berkeley between (plus lesser contemporaries). German philosophy waxed golden from 1780-1829, with Kant, Fichte, Hegel, and Schopenhauer, plus. The question, then, is whether Anglophone philosophy from 1950-1999 might be roughly comparable.
To a first approximation, two things make a philosopher great: quality of argument and creative vigor. (Personally, I also rather care about prose style, but let's set that issue aside.) With apologies to Kant enthusiasts, it seems to me that despite his creativity and vision, Kant's arguments are often rather poor or gestural, requiring substantial reconstruction by sympathetic (sometimes overly charitable?) later commentators. And Descartes' major positive project in the Meditations, his proof of the existence of God and the external world, is widely recognized to be a rather shoddy argument. Similar remarks apply to Plato, Hegel, Spinoza, etc. The great philosophers of the past had, of course, their moments of argumentative brilliance, but for rigor of argument, I think it's hard to say that any fifty-year period clearly exceeds the highlight moments of the best philosophers from 1950-1999.
The more common complaint against Anglophone "analytic" philosophy of the period is its lack of broad-visioned creativity. On that issue, I think it's very hard to justify a judgment without the distance of history. But still... in my own area, philosophy of mind, the period was the great period of philosophical materialism. Although there had been materialists before, it was only in this period that materialism really came to full fruition. And arguably, there is no more important issue in all of philosophy than the cluster of issues around materialism, dualism, and idealism. From a world-historical perspective, the development of materialism was arguably a philosophical achievement of the very highest magnitude. The period also saw a flourishing of philosophy of language in Kripke and reactions to him. In epistemology, the concept of knowledge came under really careful scrutiny for the first time. In general metaphysics, there was David Lewis. Wittgenstein's Philosophical Investigations also falls within the period. In philosophy of science, Kuhn. In ethics and political philosophy, Rawls and Williams. Without pretending a complete or unbiased list, I might also mention Strawson, Putnam, Foot, Singer, Quine, Anscombe, Davidson, Searle, Fodor, Dretske, Dennett, Millikan, and early Chalmers. In toto, is it clear that there's less philosophical value here than in the period from Descartes through Locke or from Kant through Hegel?
Or am I just stuck with a worm's-eye view in which my elders loom too large, and all of this will someday rightly be seen as no more significant than, say, Italian philosophy in the time of Vico or Chinese philosophy in the time of Wang Yangming?