Remember when you used to ask your Mom / Dad, "Why?" and they'd respond with, "Because I said so." It's like that, but subtly more infuriating because it's never a single identifiable person saying "no" that could be spoken to, understood, and reasoned with. The answer that you'll get at a big company is, "because that's the way it is".
Having worked at Big Co and then on my own company for years, this is exactly what I was thinking. You'll lose professional autonomy in exchange for a good salary, job security, and resume bling. And you probably won't have to work as hard or as often (again, probably).
Everything has tradeoffs and sometimes the cost to change something is higher than the benefits gained, but the people I work with are always willing to listen.