[alaties]

I'm not sure this statement is generally true for Netflix's use case.

UDP provides no out of order packet handling which _needs_ to be handled for video streaming. UDP is by default unbuffered throughout transport and tends to cause greater stress to client systems since they need to respond per packet rather than per traffic stream (IP+port combo). As a client developer, you end up reimplementing 90-95% of what TCP gives you out of the box at great development and QA cost. You also drain battery on mobile devices with all the interrupts your causing doing UDP. The upside with a UDP-based implementation is the latency from server to client display is usually much less (tens of milliseconds vs hundreds to thousands), but the trade-offs involved are almost never worth it for a static media streaming site like Netflix.

Even dynamic media streaming sites like Twitch rarely dip into UDP server-client implementations unless there are some unusual requirements.