you are right, it is a naive high level view and a deeper analysis is probably warranted... but i think its a pretty defensible position once you start looking at details, and especially if you are willing to lay the entire of WW2 at his doorstep... certainly in terms of human life lost and impact to industry and economy, its hard to think of a 'single event' from the past 100 years that even comes close.
These are good examples, Henry Ford is an especially good example, as the pioneer of much of what we consider to be common sense or standard working practices today.
I'd disagree on Oppenheimer though - other than his media popularity for the famous comment on the atom bomb and the trial, his contributions to physics, whilst considerable, are easily trumped by his contemporaries in that field. Dirac, Feynmann, Einstein, Pauli, Fermi to name a few...
Its an interesting topic for discussion to be fair. Probably worth more thought than I give it credit...
http://www.npr.org/programs/morning/features/2002/jul/fritzh... ber/