I wish that hypo situation was my case. I feel the same way as you do.
I feel unsure about whether or not I am top school material as well, due to my undergrad institute, WE, and I also haven't taken the GMAT. However, like yourself, I am very dedicated to get into a top b school.
I am very glad I found this forum as well. Great quality information by a lot of amazing individuals. I just hope that I will learn enough to provide quality information as well in the near future. I also hope that we can create some sort of gmatclub network as well.
Back to answering your question, I think only a small percentage get in to top b schools with minimal effort. This could be answered by talking to 1st and 2nd year students during campus visits. I do think most on this forum are 'exceptional', and people on this forum are individuals who carefully researched their options to get the best ROI. Also, I do not know a lot of people who go onto forums, browse countless hours reading other peoples comments and post, then contemplate over the information present and then make informed decisions based on this knowledge.