Maintaining infinite platform/device compatibility, optimising video delivery, reducing bandwidth costs and new features to push the medium forward (like the choose-your-own-adventure thing they made).
Video delivery is hard. If you spend a month working on a basic Netflix clone showing a single clip it won't be 1/100th the performance of Netflix even if you use a CDN.
Netflix has optimizations for individual ISPs by placing content servers directly in their DCs.
Also, large organizations accumulate constant tech debt that need to be paid down. Features aren't infinitely scalable.
Video delivery is hard. If you spend a month working on a basic Netflix clone showing a single clip it won't be 1/100th the performance of Netflix even if you use a CDN.
Netflix has optimizations for individual ISPs by placing content servers directly in their DCs.
Also, large organizations accumulate constant tech debt that need to be paid down. Features aren't infinitely scalable.