The Indian subcontinent was the birthplace of Buddhism. The teaching of Buddha found lots of success in foreign lands such as China, Myanmar, and Indochina. Yet in its homeland, it is currently a very small minority. How could this be?

I am an undergraduate who did a thesis on ‘Vedanta’ which, in a nutshell can be said as Hinduism’s response to Buddhism arrival. Now I’ll declare before hand that besides the philosophical arguments of Buddhism, I am not aware of the social and economic dynamics of the the interplay between Buddhism and Hinduism but I can give you a story from a Vedantic or philosophical perspective.

The history of religions in the Indian subcontinent is far too old and even when Buddhism arrived during Gautama’s time, the vedas, i.e. the principal Hindu scriptures were ancient.

As is with anything ancient, time had led people to draw their own conclusions from it’s teachings and six principal schools of Vedic interpretation were already flourishing. These were together called ‘ShadDarshan’ or 6 perspectives of the Vedas. Although there was infighting among the interpretations of the Vedic scripture, the scripture itself was and still is considered super natural in origin and thus, no view or ideology or practice is to be in direct violation of the Vedas.

Basically, you can interpret them the way you want to but cannot deny them. To deny the divinity of the vedas was something the six other schools would unitedly stand against. Now one must also understand that no such thing as Hinduism formally existed back then. There were these six major philosophical schools, each with their own sets of religious practices and then there were minor pantheons of fire and nature worshippers along with gods associated with tribal folklore. Since the six major schools were undeniably upholding Vedas as supreme scripture, even the minor, unorganised , tribal religions tried to somehow justify their practice as being based out of some or the other Vedic source. That was the trend of the time.

Buddha, singlehandedly established a strong philosophy complete and complex enough to stand and defeat the established six schools of the time. Although he did borrow a lot of Vedic concepts like that of Karma, Reincarnation, Aatma, etc but Buddha simply rejected the authority of the Vedas. He did this by introducing, among other things, the concept of non violence in his philosophical doctrine which meant certain yajna sacrifices (which involved animal killing) which were common practice in the Vedic schools were not to be done anymore. Many Indian kings gave patronage to his doctrine with Emperor Ashoka being the most popular, who commissioned the construction of thousands of edicts, stupas, and was singlehandedly responsible was Buddhisms reach to Shri Lanka and Burma. However, for the the the common Indian people, there already were the six schools, and the other smaller pantheons. Buddhism was just another new option thrown into the mix. The common man simply wouldn’t be interested in the intricacies of the many schools and commonalities between them were the only things that reached them. The commonality was, to Buddhism’s disadvantage, the Vedas. Just as Buddhism adapted certain concepts from the Vedas, the six Hindu schools, over time began adapting the concepts from Buddhism. Newer schools emerged which took both, Vedic and Buddhist ideologies and forced Hinduism as a whole into a kind of a renaissance.

However, the result of the renaissance was such that, the original and pure Buddhism was simply lost among borrowing of ideas, concepts and reinterpretations of the Vedas in the hundreds of years thereafter.

Today, the ideas of Gautama exist in Hinduism. There is a whole category of schools namely the ‘Vedantic’ schools who adapted some of Gautama’s ideas into their own ideologies while still maintaining the supremacy of the Vedas.

TLDR: Buddhism was not removed from India, it simply got dissolved, merged and remoulded into the many newer schools of Hinduism which emerged during the Hindu renaissance which Buddhism itself triggered.