> As much as this website could be very trafficked I have the feeling they are overcomplicating their infra,

That is because they are and it seems that since they're making billions and are already profitable, they're less likely to change / optimize anything.*

Netflix is stuck with many Java technologies with all their fundamental issues and limitations. Whenever they need to 'optimize' any bottlenecks, their solution somehow is to continue over-engineering their architecture over the most tiniest offerings (other than their flagship website).

There is little reason for any startup to copy this architectural monstrosity just for attention on their engineering blog post for little to no advantage whatsoever.

* Unless you are not profitable, costs of infra continues to increase or the quality of service is sluggish or it is urgent to do so.