Good question! I've pondered this myself for years. Why do people so tenaciously cling to corporate ideology - even when excessive corporate power has real tangible negative consequences for their lives? Here's some reasons I've come up with, along with my estimate of the proportion of people in question that reason applies to.
1. They're an Authoritarian personality. (70%) A good many people in any society simply instinctually defend any existing power structure. It wouldn't matter if the existing power structure were a powerful priestly class, a communist Stalinist terror-ocracy, or the corporate-hegemonic state of today. People cast their lot with the powers that be. Not a lot of reasoning or self-awareness going on here.
2. They have a lot vested in the current order (15%) Sure, the evidence is all there about how all this corporate power is literally destroying the earth. But what if you are in a powerful / easy / cushy / advantaged position that you like, or think you like? This is where people embrace all sorts of easy thought patches. For instance, a common one is to cite the failure of the Soviet Union and use that as a reason that the economic status quo should never be tinkered with, except of course when it is tinkered with to their advantage with tax breaks, corporate welfare, and the like. In fact this is so common and unquestioned I daresay it is now instinct in most Americans. It is certainly unquestioned and even reinforced in our national dialogue. Another instance is where people refuse to take responsibility for the world they are creating. 'Hey, dealing with all these questions is someone else's job. I'm just doing mine.'
3. They're too busy working to consider what is really important in life (10%) Put in that 80 hour week in the investment bank / assembly line / restaurant / whatever.. Drag yourself home half alive just in time to collapse into bed. Use your few free hours on the weekend to numb the pain with drink / sex / television. Repeat. Chances are you've lost track of all priorities. What does it matter to you if a wilderness remains pristine, if you're never going to get to camp in it without your laptop? What does it matter if your kids are bombarded with fast food ads all day at school, since you're never going to be able to prepare them anything else? What does it matter if your shirt was made by kids in Guatemala chained to sewing machines? You're chained to a desk, and you're in no rush to help anyone else. All these negative results of corporate power that other people seem to be 'bitching' about all the time have no meaning to you.
4. They're just plain evil people. (2%) There are many out there who just plain old take pleasure in others' misfortune. When bad things happen, as long as it doesn't happen to them, it's a laugh riot. There are all sorts of psycho-sexual desires at play here, as with the authoritarian personality. The end result is that any system that enslaves and embitters people is a-ok with them.
5. They have really and truly considered all of the options available, and after a great amount of thought and reasoned debate with others have honestly concluded that the status-quo structure of extreme corporate power is the most beneficial socio-economic system available (3%) I just plain old disagree with them, but I do recognize an intellectual conclusion as opposed to a gut-level conclusion, and I respect them for that. They and their open minds might want to check out The Faulty Reasoning of Ayn Rand Types, and I hope in the future they can point me to sources that make me question my conclusions.