[kevindong]

If the initial cost is x engineer hours and each hour costs $y, that implies the cost of the project is `x * $y + maintenance costs [of this system over the simpler, original approach]`

Is the increased speed worth `x * $y + maintenance costs`?

Could it pay off? Potentially yes. Will it actually pay off? I don't know since there's far too many variables to wildly speculate on. But I hope Netflix did the accounting at some point along the way to find out.

Not every improvement is worth building since the initial investment might grossly overshadow any potential gains (as a purely hypothetical situation, that's why you shouldn't spend $1 million up front to save $1/day for the next 30 years).