I regret the fact that so much graduate education, and so much philosophical writing sets itself in dialog with a recent “literature”, with a tiny readership. History of philosophy is often healthier than “systematic” philosophy, precisely because it inherits the wider focus that was so typical of the career of culturally significant philosophy, from Plato and Aristotle, through Kant and Mill, to Dewey and Rawls. My article is intended to encourage those who want to think and write with a larger frame of reference.But I think if the final point was Kitcher's primary aim, then perhaps he could have done that without being, as it seems, fairly dismissive of the "core." I don't work in the "core areas," and so have no stake in this per se. Kitcher's worry--as others have suggested--is perhaps described even more succinctly by Dennett: getting caught up in a cottage industry with a limited shelf life and a very narrow audience can be a problem.
I tend to think that the best thing to do is to follow one's philosophical interests, and what Kitcher is (I take it) trying to do is to encourage (especially young) philosophers not to confuse that with simply trying to keep up with and respond to all the current literature on one's interests (though doing some of that is surely important), and not to be afraid to "think and write with a larger frame of reference," which may mean that much of one's time must be spent doing other things besides carefully reading every article in the latest issue of, say, The Journal of Philosophy. There are too many things to do within philosophy, and too many interesting topics, and too many interesting puzzles. There are also people to meet (outside of philosophy), novels to read and films to view, science to learn about. And of course, there's the world to be saved. (More on that another time.)
Obviously, jumping onto a particular philosophical bandwagon (or contributing some "cottage industry") can be a way to get one's foot in various doors (to produce a publishable article, etc.), and doing some of that may be unavoidable (and even desirable). But perhaps there's more to being a Philosopher (capital "P") than being a good professional philosopher, and perhaps that's part of Kitcher's point. (The capital P doesn't have anything in particular to do with being "famous" or whatnot.) Some may not like that distinction, but for me, outside of the academy, I don't like being introduced (say, by my wife) as "a philosopher." I teach philosophy, and have published some articles in academic philosophy journals. But I generally don't feel like I am yet a Philosopher. (Sorry if that sounds sort of pathetic; this isn't a self-pity thing, I hope!) Figuring out how to become that has been on my mind ever since I finished my dissertation, and realized that I was now free to write and pursue whatever issues I chose to pursue. That is at once liberating and terrifying. (And maybe that's why it's easy to get pulled into a "cottage industry" as it were.)