Corporatism is a different animal. It serves the corporate entity, not the individual. By theory, those corporations which best serve their own needs at society's expense, or which best serve other corporations will thrive. The individual becomes prey. Society, sensing a threat, seeks protection through socialistic legislation. The corporate animal either seeks a way around this legislation or flees to somewhere beyond its jurisdiction. Corporations also use their weight to insulate themselves against honest competition by exerting influence upon government. That's right! Corporations also seek to expand the reach and size of government for their own benefit.
Well, a couple of things. Spencer, who coined the phrase "survival of the fittest," pre-dated Dawrin. He was talking about corporations.
The other thing is that you're judging business morality and benefit to society only by size. Seems a little arbitrary and tough to prove. There were few giant corporations in the victorian era in London, yet it was a hugely brutal time.
Lastly, your thesis seems to be:
Big corporations = bad
Mitigating force of government = bad
The only good business entity is a small business entity.
In truth, small business entities are incapable of doing certain things. For instance, a hundred years ago they couldn't build a railroad. Today, they can't do nanotech...these are both enterprises that need specific skill sets, capital and manpower.