Did you even read it. There were struggles with Brahmins, but those were political struggles, not existential.
Muslim invaders eliminated them forever from India. Read this section: https://en.wikipedia.org/wiki/Persecution_of_Buddhists#Perse...
PS: https://en.wikipedia.org/wiki/Persecution_of_Buddhists
EDIT: https://medium.com/@ArainGang/hindu-persecution-of-buddhists...