There is no unitary religion called Hinduism. It is like calling a ‘miscellaneous ‘ as a defined class called ‘miscellaneous’. All civilizations start off with ‘animist’ beliefs, proceed through anthropomorphic gods, polytheism, monotheism etc. This is part of ‘conceptual’ reduction acting at human social cognition. The vedic tradition is the animistic first stage of human social cognition. Buddhism, on the contrary, was somewhat an aberration with a premature transition to agnosticism, something which never had happened anywhere, way ahead of every other example of social cognition. However, dispersed among the ‘Vedic tradition. were strands of sophisticated thinking. These later philosophies had very little similarities with the canonical Vedic practices. There are about 100 odd Upanishads, but only a few are considered as ‘part’ of the real core. Many are copycats of one another. Few British and Germans missionaries and scholars who came to India and studied Upanishads used it to disown their Semitic Jewish heritage because they wanted to disown Judaism from their heritage. They considered the Veda generating Indian as their original cousin brothers, and constructed an elaborate story on it. Indian Hindu revivalist like Dayananda Saraswati and Vivekananda built on this thesis and weaved a story that there is ‘uniform’ religion called Hinduism that had continuity throughout the Indian subcontinent. In fact, the basic texts alleged to that of Hinduism is not that of the ‘alleged’ Hindus but that of select few Brahmin practitioners.
India is land that has lost its renaissance religion. We still are in the dark ages. Vivekananda and Dayanand Saraswati et al. are torchbearers of that dark ages.