Gotta love the useless comparisons..."an eighth of the time that powered flight has existed".
Things that took less time than the F-35:
The Beatles entire career as a band.
The Apollo program from Kennedy's speech to Neil Armstrong.
The combined timelines of WWI and WWII.
Both Mars rovers were proposed, approved, developed, launched, and have been on Mars for over 3 years.
The entire construction, from proposal to completion, of: The Golden Gate Bridge, the World Trade Center, the Empire State Building, the Suez Canal, and the Channel Tunnel.
The Manhattan Project.
Alexander the Great's conquest of Persia.
Caesar's conquest of Gaul.
The Wright brothers' first airplane, from conception to Kittyhawk.