Not that Buddhism became the dominant religion either, but it made such a tremendous impact that Hinduism later tried to incorporate Buddhism into itself to close the gap on the cognitive dissonance of how such a "heresy" nearly drowned the local religions. Hence why some Hindus traditionally regard the Buddha as the 9th Avatar of Vishnu.
Scientific Potential
Indian religions also carried very strong scientific potential if developed further. I dare say in OTL they have had an impact, probably via Buddhism along the Silk Road and the merging with Western philosophy. But in TTL, even if Jainism replaces Buddhism, there is still strong potential there.
Interesting thing about Jainism is that it has one the most developed Atomic theory of all of the ancient philosophies. That is, they included subatomic particles and positive and negative charges.
https://en.wikipedia.org/wiki/Jain_philosophy#Atomism
Buddhism however, also have Kalapas.
https://en.wikipedia.org/wiki/Kalapa_(atomism)
There was also a lot of early science within the Vedic scriptures as well