Some people, even after many months of training and many hours of classroom lessons and private tutoring sessions, feel that they are never going to be in a position to improve their scores enough to break the 650, that magical number that seems to be a sort of glass ceiling for the standard "top MBA" programs (by which we mean the gamme of Wharton, HBS, Columbia, Stanford, Chicago Booth, Kellogg, Sloan, INSEAD, LBS, IMD IESE, Bocconi, HEC and the like). Is this really possible?
It might be. Remember: the GMAT is a very well-crafted test with a significant psychometric dimension. That means it tests your mental abilities more than what you have learned, and consequently it is a very hard test to "learn." No test is foolproof, of course, but there are reasonable limits to how far humans can stretch their own abilites, mental or otherwise. For example, someone who was never particularly keen on math in high school is going to have a lot of work to do on the Quant section. And the older one gets, the more difficult it will be to form new neural connections and increase one's abilities in remarkably weak areas.
So for some people, even very well-educated people with good careers, the peak score will not be around 650 to 750 but around 500 to 600. At this point, you need to forget the big guns and explore other options. But what? and how?