Yeah this idea that it doesn't matter if you win or do well in tour matches, I don't buy at all. Winning and losing are habits for any team and, probably, the more difficult the opponent, the more critical it is. When Australia lost the Ashes in '05, they were smashed by a couple of county teams along the way, annihilated in the T20 (telling everyone along the way none of it mattered, of course). It was clear their form was pretty uneven as the Test and ODI's series' showed. Their good form in the second ODI carried over into a Test win at Lords but I remember the feeling from Vaughan was that England would come back even if the press slaughtered them.
In India and SL, tour match form has fairly well predicted who has done well in the Tests. When Australia won in '04, they had the better of the match against Mumbai and bashed the Board President's XI in SL but other times when they've been hammered in the Tests, it's been on the back of losses in the tour matches. You might get less out of belting some FC team in tour matches from an individual perspective but the team gains are far more important, for mine.