[cname]

Well, there's also massive scaling, which the average web developer isn't experienced with. Then there's creating a consistent experience across various devices and browsers.

So, sure, anyway halfway competent developer could bang out a YouTube (or Facebook, etc) prototype in a few weeks, but going from there to a reliable, usable service at scale is something else altogether.

You're going to need some project managers, SREs, sysadmins, front and back end web developers, programmers who know about video encoding, content experts, lawyers, etc...