Michelin Ratings

What does the Michelin Star rating mean? The oldest restaurant rating system was originally created for hotel restaurants as a guide for travelers . 3 stars represents a restaurant that has exceptional cuisine and worth a detour, 2 stars represents a restaurant that has excellent cuisine and worth a detour and 1 star a restaurant that is interesting. After some research, I found it really hard to find the criteria in which the ratings are determined.
Based on the rating system, the assumption would be that a two star restaurant would have superior food to a one star restaurant. I had the opportunity to eat at restaurant Michael Mina in San Francisco ( 2 michelin stars).
Although the food was good (we had the taster menu) I can't say that the food was "excellent in cuisine". Although the food was seasoned well, nothing about the food screamed in my mouth.
One of the dishes that we had was a soft shell crab with heirloom tomatoes. Although the food was seasoned (a little too salty)for my liking- compared to Benares( one michelin star) in London's soft shell crab dish- Michael Mina's could not stand up. Course after course, the food was cooked well and seasoned well but there was nothing spectacular about the food. When paying that much for a meal, I expect the food to dance on my tongue and play with my senses.

The decor of the restaurant was wonderful. Soft sea foam green colors with circle patterns being subtly repeated in the carpeting, napkins, table settings etc. The service was impeccable (I even got a 30 second tour of the kitchen during dinner rush). The most impressive thing about the restaurant was that they did two full turns on a Sunday night! Deep did remind me that the 2008 Michelin star rating did just come out which always helps with reservations!
So how is it that Michael Mina's restaurant gets two stars and Benares gets one if the food in my opinion at Benares was just as good if not better (the service definitely was not.. in my opinion, the maitre d' at Benares should not be in his position that he was in)? Is it the difference in service and decor? If so, then the criteria by which michelin rates should be adjusted to note this. Has Michelin ratings become a money making machine? One must remember ultimately that the michelin star rating guide is some one's opinion and merely that- an opinion.