Veganism is not a boycott - a boycott aims to change the behaviour of a company or industry; veganism wants to end an industry.
Boycotts have a conditional end; veganism is a baseline principle that non-human animals don't deserve imprisonment torture and death.
Boycotts are reform that targets extrinsic harms, veganism targets abolition of intrinsic harms.
So saying "Veganism won't achieve abolition because boycotts have limited success" is a category error.