Veganism is simply not taking part in animal suffering, you're thinking of "animal liberation" which is the active part.

And yes one way to reduce animal suffering is to leverage basic market laws about supply and demand. But buying and selling isn't capitalism. People in every socialist nation ever have bought and sold stuff, and when stuff wasn't in demand the supply reacted accordingly. If you want an introductory book I can recommend some (earnest, not trying to be mean, it just seems like you don't know the definition of the terms you're using).

But there is also direct action, adoption of rescued animals and maybe some other stuff I can't remember right now that people that take part in animal liberation do.