Loving and hating your corporate servitude
First of all, there is no "changing it from the inside". It just doesn't exist. Whatever corporation or scummy organization you can think of, if it's large or successful or both it got that way for a reason. And that reason is not "openness to radical change". It's certainly not "openness to radical change by someone 8 tiers lower on the totem pole than the CEO". Even if such a thing were possible, in the amount of time and effort it would take you to properly infilitrate this (hypoethical I swear!) corporation, you would be forever changed by it. Scarred. Re-educated. When the moment came to finally pull the "stop doing evil" lever, you wouldn't be able to do it. You would be assimilated.
You're also not enacting much effective change if you're working a job where you can't afford your rent. For all their mealy-mouthed apologies for their massive fuck ups; all their coercion towards corporate groupthink; all their fundamental disservice to the world and even their own customers; all their ultimate submission to whatever they think their shareholders want, they still pay pretty damn well.
Your aspirational and idealistic 17 year old self would say to you now, "Fuck you. Fuck those corporate overlords. Just fucking walk." And theoretically you could. There are places you could live and jobs you could have that aren't in direct service of a coming privacy-drained Big Tech distopia. Radical change starts with the self, after all. What better way to stick it to them and simultaneously eliminate the constant cognitive dissonance of being a corporate lackey than to set out in a scary new direction?
Why not today? Why not now? Why not?
Because it's scary. Fear is a powerful motivator of human behavior, and it's very much on your mind here. What if I can't find a new job? What if I end up in just a different evil job? What if I can't pay my family's medical bills? Do I really want to trade comfort and some cognitive dissonance for discomfort and uncertainty?
The uncertainty is the real killer. The real doubt isn't whether it's possible, it's whether it would even be worth it. At the end of the day, after you've told your boss to stick his quarterly goals up his ass, the Evil Company is still there, still doing what they've always done. Your brand new shiny "clear conscious", which you put everything on the line for, may not even be as great as it seemed when you resigned for moral reasons. Would any of it really be worth it?
Bravery isn't the quality of not being afraid. It's the quality of being afraid, but acting anyway. And if cowardice is the opposite of bravery, than you are a coward. But cowardice is comfortable and cowardice pays the bills. Sometimes it's easier to accept yourself as a coward than to enact bravery in the face of an uncertain future.