Analytic philosophy was self-consciously founded a) against the great man approach to philosophy [let's call that "the magisterial approach"], and accepting, by contrast, b) the division of intellectual labor, such that c) philosophy is a collective enterprise. The rhetoric that accompanied these moves appealed to success of the sciences. (I have labeled this "Newton's Challenge to philosophy".) Now one self-conscious byproduct of this approach is that from (some baseline) progress is possible. As in the sciences, even refutations and lack of confirmation can facilitate progress. Everybody's efforts matter. Hence, the journal article replaced the lengthy monograph as the favored form of communication. If size matters, Derek Parfit is no analytic philosopher.
Joking aside, Mark Schroeder's very interesting, even moving NDPR review of Parfit's super-sized On What Matters, calls attention to a peculiar affectation of Parfit: "in more than one place [Parfit] tells us that if one of the competitors to his metaethical theory turns out to be correct, then his life 'has been wasted.'" Sure enough, checking inside his book on Amazon, I find Parfit writing, "If naturalism were true, Sidgwick, Ross, and I would have wasted much of our lives." (vol. 2, 12; see also p. 367). More astonishingly, Parfit puts such a claim also in the mouth of Sidgwick (vol 2, 303-304). The thought that there is no philosophic value (pure waste) in failure is deeply antagonistic toward the whole spirit of analytic philosophy. (Incidentally, Schroeder clearly indicates the importance of progress to Parfit's way of thinking.)
But what to make of the claim that if somebody's philosophic pilgrimage was ultimately wrong, misguided, or (worse) merely foolish, does it follow that s/he has also "wasted much" of his/her life? Certainly as an empirical question this can only be settled by further facts, such as, was one a good citizen, parent, child, lover, friend, or even mountain-climber (etc). All these ways of not wasting one's life are compatible with being a foolish philosopher. (Some involve non trivial opportunity costs, of course.) According to Wikipedia, Parfit is nearly my dad's age, so he must have a reasonable sense of how he managed (allow me a strange way of talking) the time of his life. Perhaps, we might say (and not just those of us who have read Aristotle or Montaigne), that if concern about wasting one's life is sensible, one should not place one's bets on only one worthy activity (allowing for the sake of argument, that philosophy is such an activity).
Now, it's true that if one does not reach a mountain peak, then a climb has failed; perhaps one might even consider such a climb wasted. (I use this example because Parfit embraces (according to Schroeder) "the thesis that moral progress is possible. At the culmination of volume 1, Parfit writes: “It has been widely believed that there are such deep disagreements between Kantians, Contractualists, and Consequentialists. That, I have argued, is not true. These people are climbing the mountain on different sides.” (vol. 1, 419)") Clearly Parfit thinks those of us in moral philosophy should be climbing HIS mountain. But this idea (that one's life is wasted if one happens to be climbing the wrong mountain) is evidence of a certain kind of fanaticism (however, well argued). Not only does Parfit embrace moral monism, he embraces human monism (for him--Parfit may be more tolerant toward others). Some might agree with Parfit that aiming for the right moral-theoretical target is what's necessary for worthy living, but I wonder if even these will all agree that it is sufficient. For, how much of one's life must remain unexamined if one climbs a mountain and while mapping it, one IS PUSHING others along it! Either way, such human monism is a form of fundamentalism in thought that is the disease of our times.