I don’t always (or often) agree with Heidegger. But these remarks from the Introduction to Metaphysics seem to be mostly right.
Very roughly speaking, philosophy always aims at the first and last grounds of beings, and it does so in such a way that human beings themselves, with respect to their way of being, are emphatically interpreted and given an aim. This readily gives the impression that philosophy can and must provide a foundation for the current and future historical Dasein of a people in every age, a foundation for building culture. But such expectations and requirements demand too much of the capability and essence of philosophy. Usually, this excessive demand takes the form of finding fault with philosophy. One says, for example, that because metaphysics did not contribute to preparing the revolution, it must be rejected. That is just as clever as saying that because one cannot fly with a carpenter’s bench, it should be thrown away. Philosophy can never directly supply the forces and create the mechanisms and opportunities that bring about a historical state of affairs, if only because philosophy is always the direct concern of the few. Which few? The ones who transform creatively, who unsettle things. It spreads only indirectly, on back roads that can never be charted in advance, and then finally — sometime, when it has long since been forgotten as originary philosophy — it sinks away in the form of one of Dasein’s truisms.
The translation is the Fried and Polt one from 2000, not the old Manheim translation. I only altered the very first line, adding the “very” since the original text starts with ganz. The above remarks appear on pp. 10-11 of the Fried and Polt edition.
I think it is often true that philosophy does not immediately impact a culture but that its ideas do (for better or for worse) slowly trickle down to the general population and in the end, quite strangely, become “truisms.” I wonder, however, if this trickling down is happening faster now with more people getting college educations and with the hyper-development of communication media.