> Pointing out an egregious case of advertising that does not deliver a net positive does not disprove that point.

Coke/Pepsi were your own examples. I don't believe there are just a limited number of bad cases in an otherwise good system, but rather that at it's core is a huge zero-sum game of burning resources to take market share back and forth, with even the non-zero-sum impacts (people hearing more about sugary drinks instead of other things, and consuming more sugary drinks than they otherwise would) being of questionable value in most cases (in some cases potentially good, but still disproportionately small benefit compared to resource wastage).

I think it's similar to Bitcoin mining as an example of what happens when competition is not directed towards a useful end like improving the product.

> But from that extrapolating that all advertising is bad and calling all jobs related to it as useless is excessive.

A job working on serving web ads is almost guarenteed to be a net negative to society in my eyes.

I wouldn't really consider someone writing a travel blog to be working in advertising (unless they get paid to push certain destinations) and I don't think anyone here's claiming that to be useless.