For your information, the caste system was introduced to India by the British, as a structure to economically exploit India which was the sole reason the British invaded India. My family was taken to South Africa in the mid-1800s as indentured slaves. Caste does not and never has existed in our community. The reason for this is that caste was introduced by the British after my family left India.
The birth based caste system the British introduced was a weaponization of the occupational Varna system in which individuals followed occupations that they had natural aptitudes towards. The Vedic scriptures make no mention of caste. The word Caste comes from the Portuguese word casta which means class. I urge you to read the book Varna, Jati and Caste by Rajiv Malhotra, it provides a well researched academic analysis on this topic.
As for Wilkinsons book, it is the literary version of the “India no toilet” meme. I am surprised that nobody has brought a lawsuit against her.