I suppose raises the question, is the spending of mega bucks on advertising (regardless of effectiveness) a net benefit for society?
As commenters have already raised, we'd have no Google, Facebook, Twitter (sorry 'X') or many other entities and the products they create without the money spent on advertising. Is this all just happening because people are too scared to look under the curtain and find that it's all just a sham?
We had advertising long before the internet came along, and from my personal memory most of the most aggressive advertising was for things that were either useless (magic snake oil remedies) or actually dangerous (tobacco products), not to mention all the "as seen on TV" junk that was "promoted" on morning television.
Is what we have now is more intrusive? It used to be that you could duck to the toilet during the adds on TV or flip the page in the newspaper or magazine, but now they are taking our cpu cycles, making web pages unreadable and that is not to mention the more intrusive ways of really getting in our heads.
I'd argue that we've always had (even if just the shop keeper recommending a product) and always will have advertising. There have always been products that are not needed or wanted by the majority, and advertising is the way that the producer of that product gets their product sold. I would be nice if there were not so much dodgy practice involved.