
Why isn't Hinduism adopted by people interested in Neo-Paganism?
The Hindu gods are directly related to Indo-European gods. Indra, for example, is equivalent to Zeus and Thor, not just archetypically but a direct branch of the same original idea of the god.
Hinduism also promotes values such as pacifism, vegetarianism and animal welfare, which are often topics that overlap with the same people interested in worshipping nature-based gods, protecting nature, etc. I'm aware many Hindus don't practice such values (e.g. trash in their rivers), but it's interesting that they are codified in their doctrine, with a continued authoritative tradition. Just as in every religion, it's only a minority that truly practices all its values and rituals.
India is also a country rich in tradition, culture, food traditions, and ancient connections to European people.
It also makes perfect sense to adopt and adapt the gods that are closely related to those of your ancestors, even if from another religion, than to just reconstruct long lost rituals with no continuation.
TLDR: It makes more sense for neopagans to adopt Hinduism than to create a new religion with old gods are labels.