I think its less an ad bubble and more like something similar to government use it or lose it spending. There is a sort of global hot potato/musical chairs thing going on. No one wants to be the first or last one to cut their ad spending so its a stand off.

I've looked at some ad spending stuff at companies in the past and while their official numbers always "added up" there always seemed to me to be huge logic gaps that missed lots of obvious overspending. Those things are always hand-waved away as some sort of force multiplier or other nonsense. AKA don't cut our budget or sales will go away we dare you!

I've posted a longer comment on here about an adventure in cutting ad spending at a company I was at because of a minor feud I had with the marketing manager. There were huge areas where the cost/profit from ads was destroying profit margin. I made some tremendous efforts to prove we could make major spending cuts on advertising without losing sales to the owner and ceo and was successful. I probably would not have been able to do it if the marketing guy was not constantly blaming their failures on IT so I stood up for us by spending my personal time making accurate reports and dashboards about the spending and proved him wrong. (he and a couple others lost their job) (no they didn't stand up and clap its a real story)

This doesn't happen enough. Past 10-15 years or so, thanks to tech overwhelming them, Marketing depts have lost their way. Its not their fault. They get all their training from google, youtube, fb etc on how to think about these systems and when things dont work out the usual reaction is, but we are just doing what Google/FB told us to do.

>They get all their training from google, youtube, fb

Not sure if you are sarcastic or not. I totally blame them. I mean would you ask your drug dealer how to quit drugs?