Let me share with you some of my thought based on my reading on caste among non Hindus. Though traditional Hindu caste system is rejected in the Islamic and Christian text, there exist groups such as Sayid, Sheikh, Pathan dnd Momin (in India) which function as exclusive endogamous caste groups. Similar stratification can be observed among the Christians who are divided into a number of endogamous groups including Chaldean Syrians, Jacobite Syrians, Latin Catholics etc. Even among the Catholics, Syrian Romans and the Latin Romans generally do not intermarry.
I believe in a society which gap between the rich and the poor are very much widen, caste exists. Some Islamic religious scholars believe that the status inconsistency is an inevitable by product of God Creation for the less fortunate group to serve the well fortunate one and for the well fortunate groups to serve God through paying sedeqah and zakat to the less fortunate one and in a way creates homeostasis in the society.
To the contrary, I believe, poverty can be eradicated and people can still serve God without having some groups to be superior than the other. The right Islamic teaching is to advocate the true value of individual right and human dignity.