Reading the article I got the impression the big challenge is doing "personalzation" of the content at scale.
If it were "just" static pages, served the same to everyone, then it's pretty straightforward to implement even at the >300m users scale Netflix operates at. If you need to serve >300m _different_ pages, each built in real-time with a high-bar p95 SLO then I can see it getting complicated pretty quickly in a way that could conceivably justify this level of "over engineering".
To be honest though, I know very little about this problem beyond my intuition, so someone could tell me the above is super easy!
If it were "just" static pages, served the same to everyone, then it's pretty straightforward to implement even at the >300m users scale Netflix operates at. If you need to serve >300m _different_ pages, each built in real-time with a high-bar p95 SLO then I can see it getting complicated pretty quickly in a way that could conceivably justify this level of "over engineering".
To be honest though, I know very little about this problem beyond my intuition, so someone could tell me the above is super easy!