The most salient reason why corporations go public is to sell shares to the general public, thereby paying back and rewarding the original private investors with the proceeds from that stock issuance, which oftentimes, can be quite considerable – in addition to that corporation also receiving in return a massive infusion of new capital from those of the public that bought those shares. However, once a company becomes public, not only do the public shareholders have some say, but also public corporations are prone to suffering from certain investors of that public thus being able to exert pressure upon management should they feel some degree of dissatisfaction; in addition to the fact, that the company is susceptible to being under the microscope, in regards to expected quarterly earnings, from TV financial programs and pundits.
When it comes to private corporations, they are to the general public, for the most part, pretty invisible, seemingly looked upon as just regular corporations, of no real import, one way or another. This may indeed be true for the lion's share of private corporations -- for the bulk of those private corporations aren't all that big in the sense of employees, sales, or influence. However, it is the exceptions to that rule that make some of these private corporations, a real force of nature.
The biggest advantage that any private corporation has, is the fact that the corporation does not need to answer to any other entity or organization other than to those that are the owners of that private corporation, which typically consists of a select few that were the founders of such, or related to those founders, or those that the founders specifically brought in, so as to grow the corporation. Further, a significant amount of public companies, pay out dividends each and every year to their stockholders, as a ways and means to share some of those profits, so being made by that company, and to encourage those that are its stockholders to continue with their investment, over the long term; and this expenditure of money is definitely money that has left that public corporation to go to those that are its stockholders, of which, that money can easily represent to that corporation a very large sum of capital and therefore of its profits, so leaving that corporation on an annual basis. On the other hand, in regards to private corporations, because they are private, they don't have any dividends to pay, which means, that the profits so being generated can be continually invested into, for instance, the buying out or the investment of other enterprises, or things of that sort.
This so signifies that once a private corporation reaches the stage in which they are able to consistently make good profits, that they therefore are in a very good strategic position, which provides them with the flexibility and the maneuverability to get business done, with thereby an absolute minimum of outside agitation or pushback, which allows them to pursue whatever business arrangement that they best see fit, thereby giving these private corporations an enviable amount of dexterity to get accomplished business deals that make good sense for them. In short, private corporations that have access to the capital so needed or have generated such, have created a clear pathway that arguably will permit them to grow at a faster pace than public companies, for they need not pay out any dividends, nor answer to public shareholders, which has eliminated those inconvenient obstacles and puts them instead into a very strong business position.