I accept the blame here for sloppy thinking/writing; I should've expressed my initial statement more narrowly, instead of tightening it throughout the discussion.
As you correctly observe, the statement "people wouldn't buy what they need without advertising" is obviously wrong. What I was getting at was manufactured demand, and my belief that it's a significant part of non-immediate-need purchases.
Ah OK. You also had the misfortune of accidentally expressing something I've seen people here express sincerely before, which is why I didn't assume the more charitable, less-consistent with your comment's meaning.
I don't have any disagreement with the claim that some demand is advertising-generated (in fact, it's a non-trivial part of advertising's purpose). Thanks for clarifying!
As you correctly observe, the statement "people wouldn't buy what they need without advertising" is obviously wrong. What I was getting at was manufactured demand, and my belief that it's a significant part of non-immediate-need purchases.