I am glad that you have a copy of Gita with you. Apart from the Swamijee's learned interpretations—you can see for yourself what is written in the 18th Chapter 67th sloka. Empiric philosophers may call it a sophistry but is a fact substantiated after all human reasoning offered by Arjuna. It is clearly said here that one should follow Sri Krishna alone. If any body makes his choice not to follow him surely he will have relative result.
Bhagavad-gita is mostly read by almost all classes of people of the world but unfortunately they are accepted in an independant choice of indirect interpretation. That is a deviation and for that reason only they cannot derive the direct benefit.