The goal is growth and consolidation. They want every major industry to be completely dominated by a small handful of big players. This makes it much easier to regulate and implement policy.
It would be impossible for them to have nearly the same amount of control over a economy if the economy was dominated by hundreds or thousands of small and medium players. By having 3 or 4 major public corporations they are much more easier to manipulate and keep tabs on. They can 'invite them to the table' to advise and help draft policy and regulations that are mutually beneficial. Also it makes it much easier to convince the public that such regulation is done for the public's benefit.
This model of American State Corporatism was developed in the late 19th, early 20th century and has since been exported across the world.
It is a pattern that is repeated over and over again. Whether it's automobile manufacturing, steel manufacturing, railway transportation, television broadcasting, ISPs, or Social Media.. once the government set it's sites on regulating it you will see markets devolve into 3-5 major corporate players that pretty much control everybody else. All of this heavily encouraged through regulation of capital markets and central banking systems.
The classic pre-internet example is the development of AT&T monopoly. FCC used it's ability to regulate peering agreements to heavily favor the markets towards re-establishing the AT&T monopoly. A monopoly that they essentially lost when the early Bell patents ran out.
They were then able to use that monopoly, through regulatory forces, to gain control over the communication infrastructure during the cold war, which was a national security priority. That is how we ended up with things like Room 641A. (which was in 2003-later era, but is something they did through out the entire cold war)
History repeated itself with the Prism revelations.