Of course the idea of an "Advertising Economy" should cause people to pause a bit since advertising, by its nature, can only help maximize profits for somebody else. In theory the money that gets pumped into advertising can only be squeezed from the profits of other companies who are doing some optimization, weighing the cost of advertising vs the increase in their market. The maximum amount it makes sense to pay an advertiser is proportional to the increase in the audience they provide, with the assumption that your profit - fee * population_ads > profit * population_no_ads.
One thing should be very clear, advertising cannot create value, it can only extract some of the surplus value that other companies are creating. This puts a pretty hard limit on how big advertisers can grow.
The solution to this was of course to take the byproduct of advertising, the generation of large amounts of demographic data, and transform that into a product. Suddenly selling, sorting and manipulating data create an entirely new class of products and create demand for new professionals as well.
The advertising industry, specializing in creating the illusion of value when their may be none, has done a brilliant job of convincing everyone that data is inherently values. Allowing tech companies to sell not only their data, that is often of questionable actual value, but the infrastructure to use this data, and sell training in the skills necessary to work with big data.
The "data economy" is just advertising turned in on itself. Anyone who works with data knows deep down that all of this is a farce, but I think we still have a bit of time before all of this hits the fan, so enjoy the ride.