I believe the main cost is in hosting all the videos. A lot of them are probably junk that were never meant to see the light of day. I certainly use it as an extra backup for many of my videos with no context and random UUID titles.

For everything else, a potential solution is to have everyone come in with their own videos hosted elsewhere and the platform just integrated with a bunch of APIs for fetching and serving those videos. For small time creators, the cost should be fairly low to none since a lot of platforms allow you to store a small number of files for free.