Thanks for this. I've heard recently that, in its current form, digital advertising is extremely overpriced and propped up by misleading metrics [1] and might take a downturn in the future, but I also don't really know much about it and and that point it's just speculation.
[1] https://hbr.org/2021/02/what-digital-advertising-gets-wrong
https://www.theverge.com/2021/7/27/22596592/google-q2-2021-r...
I think it's projected to earn 20 billion this year.