Is it possible to make a ratings company to compete with the ESRB?

That's a great question. ESRB is not backed by the government. It is private and independent. It has a "certification mark" and based upon its professionalism and reputation in the community, the certifications it awards are considered worthy of adoption by others. I remember when J.D. Powers was appearing on the scene doing quality control for individual companies. Within a few years, for many reasons, the ratings of J.D. Powers became recognized as certifications of quality. You could open your own ratings company. In fact, many web sites for games have their own ratings boards based on numerous factors. The challenge is to attract the following, recognition and respect of your public. There is no "monopoly" issue here since ESRB has never been alleged to have taken any action forbidden by statute or to prevent any competition.