Maybe I am overstating a little, but all the works we see as great required staying power. Apollo was a ten year program. The Manhattan Project took 6 years to develop the bomb. Firefox took 2 years to exit beta, and the iPod took several years to pick up steam. and Tesla has been going 12 years, Space X 13.

It's not that you achieve nothing in a year tenure, but can you really accomplish anything great? Can you think of any good examples of people who showed up January 1st, changed the world, and left by Christmas?

If all long projects were great you would be right, unfortunately duration as a predictor does not positively contribute to greatness.

chrome v8 was built in 2 years: 2006 to release in 2008