Since this issue is being argued back and forth by libertarians (see here, here, and here), I figured I'd throw my own opinion out there.
As any regular reader of my blog knows, I think most "left-libertarian" predictions are pretty asinine. In left-libertarian la-la land, laissez faire will result in all of us working in small, luddite, sorry-ass co-ops with a bunch of peasants. Nobody is to become too big or successful (or happy) because those things are "scary." So we work in these dinky, shitty little co-ops that have no electricity or plumbing, and we feel guilty about whatever success we have.
In "right-libertarian" land, things are the reverse. Corporations will all be huge snarling monsters (beasts, even) that will stomp the living crap out of the working class and the environment without undue delay. They will all be huge and powerful and manly and hierarchical and unforgiving, because huge corporations kick mighty ass. (Cue right-libertarians high-fiving each other next to the beer keg.)
Which viewpoint is more right? My answer: Who knows and who cares?
Who cares how big or small businesses will be? There are no "businesses," anyway. In the end, there are only *individuals* buying and selling goods and services as they see fit. There are no "corporations," just people trading things. "Businesses" are an illusion, so worrying about their "size," or demanding that they be big or small, is nonsensical.
The entire world could be considered one really "big" business. Or, it could be considered billions of really, really small businesses--with every individual being his own "business" with his own skills for hire.
So the whole debate is pretty silly once you deconstruct it.