I suspect modern economics has many good answers as to why corporations survive and flourish, but I am innocent of deeper knowledge. I am thus free to speculate in the great blogging tradition.
My hunch is that corporations have some of the self-sustaining properties of (super)organisms (which modern biology actually considers rather corporate); in essence they have a will of their own beyond the wishes of their shareholders, stakeholders, customers, board and executives. I don't think this emergent intelligence is much above that of the proverbial amoeba, but it's enough to get by in the emergent ecosphere of cash (eg. energy) flow.
Now, I admit that's whacky. But there's a tangential connection to a different story told by reputable folk:
BBC - Radio 4 In Our Time - The Spanish InquisitionI have more to say about the Catharists, Dualism, the Graviton and consciousness , but the here I'm writing about the conclusion of these eminent scholars. They felt that the Spanish inquisition was so "successful" for so long because it took on a life of its own. The Catholic church and French aristocracy set up an effective apparatus (Bushies take note) for suppressing a proto-insurgency. In France it did its job and moved on, but the unique ecosystem of medieval Spain was much more welcoming.
... Efforts to suppress religious freedom were initially ad hoc until the establishment of an Office of Inquisition in the Middle Ages, founded in response to the growing Catharist heresy in South West France.
The Spanish Inquisition set up in 1478 surpassed all Inquisitorial activity that had preceded it in terms of its reach and length. For 350 years under Papal Decree, Jews, then Muslims and Protestants were put through the Inquisitional Court and condemned to torture, imprisonment, exile and death.
How did the early origins of the Inquisition in Medieval Europe spread to Spain? What were the motivations behind the systematic persecution of Jews, Muslims and Protestants? And what finally brought about an end to the Spanish Inquisition 350 years after it had first been decreed?
In Spain the inquisitorial apparatus served many purposes beyond those of the church, it became what I (not they) would call a self-sustaining corporate enterprise . In other words, it developed a mind of its own; the Inquisition served enough powerful people in enough ways that it stayed in business. A business run, as it turns out, by lawyers rather than theologians. (You'd think the Church would have recognized Satan's henchmen, but they're notoriously weak at that sort of thing.)
There's a theory of history to be written that tells the story of such self-sustaining 'corporate' entities across time, space and culture. Probably to be told by a neo-Marxist ....
 Actually, the draft of that post is rather conventional, despite the odd connections.
 I do have to note that the speakers seemed to dance around how much anti-semitism underlay the beginnings of the Spanish inquisition, though much of it took place after Spain had expelled all Jews. On the other hand they point out that Spain's precipitate decline over the next 500 years was in some measure due to that expulsion, abetted by their all too robust Inquisition.