There are two different assertions that should be distinguished: 1) most online advertising doesn't work 2) the revenue from online advertising will soon decl

There are two different assertions that should be distinguished: 1) most online advertising doesn't work 2) the revenue from online advertising will soon decline, perhaps precipitously I believe (1), but not (2), hence it isn't a "bubble". If you tell a CEO "hey, you're not going to be able to solve your problem with advertising", then you are in effect telling them, "there's no easy solution to your problem, you must do the much harder work of making your goods or services better". Not many CEO's will want to hear that. They will continue, I think, to spend money on advertising, including online advertising, not because it works well (it only occasionally does), but because it's easier. It's like selling someone a diet aid that says they can lose 50 pounds without having to work hard. Regardless of whether it works or not, people want to believe it does, so they will keep buying.