Advertising dollars have to be less than what a company makes on the product advertised (at least over the long term, but probably in the short term as well).

Advertising dollars have to be less than what a company makes on the product advertised (at least over the long term, but probably in the short term as well). As such, it would be wholly unsustainable for advertising to be the dominant mechanism of revenue generation globally, since that would imply that companies are spending more on advertising than they could possibly receive from selling their goods and services. Maybe I'm misunderstanding...perhaps you were referring only to businesses selling access to a web service?