It is impossible not to notice that this withdrawal of philosophy from the public conversation coincides quite closely with its disciplinization, and anyone who works as a philosopher in the current, disciplinary environment knows very well that to spend too much time engaged with public affairs and too little on disciplinary work is to court unemployment. Aristotle may have written The Athenian Constitution, but it is not an exaggeration to say that if a contemporary philosopher, employed at one of our top Universities, was to devote his time and energies to consulting on or even drafting a revision of the American Constitution — say, as part of a constitutional convention — he would fail to get tenure, on the grounds that his work had not been peer-reviewed. Such is the disincentive today for philosophers to do anything other than write the narrowest, disciplinary sort of philosophy that it is hardly a surprise that so few of us are engaged in the essential work of public affairs.
Kaufman, Daniel A. 2013. “Philosophy’s Academic Viability: A Reply to Frodeman, Briggle and Holbrook.” Social Epistemology Review and Reply Collective 2 (3): 1-5.
(The Athenian Constitution, or The Constitution of Athens, which was written either by Aristotle or his student, is generally assumed to be part of the large research project behind Aristotle's Politics. Ancients sources attribute somewhere between 150 and 170 works on Greek constitutions to Aristotle; practically none of them have survived, and this one was only rediscovered in the 19th century as part of the Oxyrhynchus find. In any case, it's certainly true that most philosophy departments wouldn't count it towards tenure. One of the things I try to make clear to my Intro students is that ideas are affected by infrastructure and practice, especially educational infrastructure and practice; this would be a case where educational infrastructure and practice provide a disincentive for philosophers to concern themselves with the world at large rather than with discussions of structured technical problems likely to be cited in further discussions of the same problem.)