How is this not a solved problem by now?
I think this is a result of most software "engineering" having become a self-licking ice cream cone. Besides mere scaling, the techniques and infrastructure should be mostly squared away.
Yes, it's all complicated, but I don't think we should excuse ourselves when we objectively fail at what we do. I'm not saying that Netflix developers are bad people, but that it doesn't matter how hard of a job it is; it was their job and what they did was inadequate to say the least.
Jonathan Blow is right.