When you say that traditionally, bigger organizations were better, do you mean they were better:
a) militarily b) in developing new technologies that make lives better c) in producing goods like trains and cars d) better at generating revenues/profits e) better at attracting the best and the brightest f) producing achievements that are remembered by historians g) all of the above
It is important to clarify this, because some of these measures of success oppose each other. For instance, the Egyptian governments were great at f) but at the expense of b).
I at first took your essay to define success as b) improving technology. But if so, the thesis is obviously wrong. Most of the great inventions of the industrial revolution were created by tinkerers and small enterprises, not large organizations. Just look at the development of the textile technology http://en.wikipedia.org/wiki/Timeline_of_clothing_and_textil... . Almost every single invention from 1600 to 1900 was developed by a startup (and many of these startups were funded by outside investors, Kleiners Perkins has nothing on the Boston Associates http://en.wikipedia.org/wiki/The_Boston_Associates ).
In your essay you predict that "large organizations will probably never again play the leading role they did up till the last quarter of the twentieth century". Are you suggesting that average company size will revert to a level lower than even 1900? Or are you saying that average company size may remain roughly the same, it's just that economic dynamism will come from startups, rather than corporate laboratories?