Interesting thread! Let me throw out some thoughts on the matter.
First...it seems to be very common to try to find someone or something to blame it on when we find we have a problem. This doesn't occur just with weight problems, but with a whole host of problems. If we are successful in finding someone on which to blame our woes, it neatly removes any and all accountability from us and for many, this is a psychologically more comfortable position to be in than assuming at least some responsibility for the situation you find yourself in. Victims tend to get a lot more sympathy than those who admit to sharing at least some of the blame for their situation.
On the other hand, if adverstising didn't work, all these corporations spending billions of dollars on it would quickly abandon it for another tactic to woo and win custmers and get people into their establisments happily ordering their product.
I don't see this as an either/or type of situation. Yes, all those tantalizing commercials that I am bombarded with multiple times daily filled with smiling, happy, trim people giving the subliminal message that if only I used that particular product, I'd be like them played a part in my choices. However...they were still my choices. Most people are savvy enough to realize that advertisers don't have their best interests at heart with commercials and ads..they're being paid by the corporations for which the ads are run to bring in customers. Conditioning may happen, but I'd like to think that I'm a little higher on the intelligence scale than Pavlov's dog who didn't, by the way, have the reasoning abilities that most humans are endowed with.
I do admit to feeling some anger at the government and various food lobbies (wheat and sugar in particular) for blatantly lying to the public about the dangers of fat and the supposed health benefits of these other products; this is how we arrived at the position of the government stating that it's perfectly okay to get up to 25% of your daily caloric intake from sugar and grains filling the bottom of the government food pyramid displayed in most schools today. The average person (which included me for quite some time) isn't going to think to question that information coming from an "official" source that they trusted to provide them with accurate information. It was a real eye-opener for me to find out how these official recommendations actually come about. It's almost like a line from X-Files applies here: "Trust no one!"
But at the end of it all, I still bear the responsibility of thinking about and learning about what good choices are for ME and then following through on that information. No matter how good the commercial, nobody at any point was standing beside me with a gun forcing me to eat a Big Mac or a Krispy Kreme...I purchased and ate those foods knowing full well they weren't the best choices I could have made and nobody had me tied to the couch forcing me to not excercise.
So...does the government and "Big food" share some of the responsibility here? Yes. Do I also share some of the responsibility? Yes.