It's just a joke about the ridiculousness that large economy dominating companies can't possibly be replaced and will last forever. Thus, instead of modern comp

It's just a joke about the ridiculousness that large economy dominating companies can't possibly be replaced and will last forever. Thus, instead of modern companies they give the example of two titans of vintage corporate might (one from several centuries ago and one more recent, just a century ago) are used instead. Ah, Hubris.