Our legal systems are set up so that exploitative megacorps have a bunch of structural advantages (megacorps are allowed to coordinate whereas workers and independent producers aren't; capital can move freely to the most convenient jurisdiction but workers can't; companies can deduct their expenses and defer their taxes but individuals can't...). Most of the things we buy aren't conscious choices (and we'd go crazy if we tried), so it's more effective and more important to have the right systems and incentives to naturally create good outcomes.