Peter Higgs, who proposed the existence of what would be dubbed the Higgs Boson, says that he wouldn't cut it if he were entering academic science today. Keep in mind that this dude won a Nobel Prize for physics a few months ago.
Higgs did an interview with The Guardian while on his way to pick up his Nobel Prize, as one does, and was pretty candid about his lack of measurable productivity in the years after he published his major theory. During his years at Edinburgh University he says that he became "an embarrassment to the department" during assessment season when everyone else was showing off the papers they had published in a given year.
Higgs retired in 1996 and attempted to further remove himself from the academic world, though he was eventually drawn back in a bit when the Large Hadron Collider at CERN started to have promising results. Higgs told The Guardian that, "Today I wouldn't get an academic job. It's as simple as that. I don't think I would be regarded as productive enough."
To be fair, there was clearly tension about Higgs's lack of productivity during his tenure, so it's not as if there was a specific point in the last few years when consistent publishing became significantly more important than it had been. Also, Higgs would definitely not be employable today given that he "says he has never sent an email, browsed the internet or even made a mobile phone call." Yeah. There's that.
But his comments do raise the question of whether the scientific community is missing out on employing some great thinkers by putting so much weight on quantity of results. Higgs says, "It's difficult to imagine how I would ever have enough peace and quiet in the present sort of climate to do what I did in 1964." [The Guardian via Digg]