Krishna, the Caste System, & the Gods
Krishna: “Everyone walks on my path, and I give each one the reward that they come to me for.” [Gita 4.11]
Arjuna: “But it doesn’t seem that way. Many people seem to walk a path that doesn’t include you at all.”
Krishna: “People who desire material success make various sacrifices. I reciprocate by empowering the gods to quickly grant worldly success.” 
Everyone walks Krishna’s path, but he is not personally involved in every neighborhood through which the innumerable branches of that path meander. He can be found personally only at the very apex and cynosure of all sub-paths.
The neighborhoods through which the byways wander are maintained by Krishna’s agents, the many gods (devas). The people walking the streets here are interested in selfish objectives, and are therefore unfit to interact directly with Sri Krishna, the entity of supra-concentrated selfless divine love. Instead they interact with his various powers with varying degrees of awareness of the divinity in them.
Arjuna: “What about those whose efforts don’t even include the gods? Those who simply work at their careers for material success, are they also on ‘your path’?”
Krishna will explain that he is the origin and empowerer of secular social systems as well:
Krishna: “The four careers, distinguished from one another on the basis of practical qualifications, spring from me.” 
As Krishna’s many-branched path meanders further into materialism we encounter four types of people on the sidewalks:
1. A few are philosophical and intellectual (brahmana)
2. Some are ambitious rulers, leaders and enforcers (kshatriya)
3. Several are entrepreneurs amassing wealth and resources (vaishya)
4. Most are simply employees obsessed with making ends meet (shudra)
These terms (brahmana, shudra, etc.) may ring an unfriendly bell, for this is indeed the seed of the deplorable, debilitating “caste system.” The clear and all-important difference between the original system and its ruined pre-modern farce, however, is that the original is based on practical qualifications (Gita 4.13 explicitly says: “guna-karma-vibhagasha”) while the farce is based solely on birth (“janma-vibhagasha”). The caste system is therefore the ball and chain of a hereditary oligarchy, while the original “catur-varna” system is a practical and natural social blueprint.