What will brahmins do when they get wealth and power in the past
Answers
Brahmins didn’t have ‘most power’, they weren’t the only groups that abused ‘lower’ castes. And their main goal wasn’t to accumulate wealth.
In all civilizations, the priestly classes which had access to the gods through scriptures, rituals etc had a symbiotic relationship with the ruling class, i.e. Kshatriyas in India. The ruling class holds the actual power.
If the realm was successful, the King is likely to believe that the success was due to the rituals of the priests and they received gifts. This was how Christianity first took off in the west, when the Roman Emperor Constantine came to believe that a victory in a war was because of his faith in the Christian god.
Presumably, similar things happened in India. Groups of Brahmins migrated around spreading their knowledge, rituals and gaining favors from Ruling classes. If they failed, they could simply try their luck in another realm.