I can speak from experience that content delivery is harder than storage. Companies like YouTube tackle the storage issue by having tiered storage levels. Trending content is stored on SSDs, new and often viewed content is stored on harddrives with a caching system similar to optane and archived storage (essentially old videos that very rarely get views) goes on tape storage. It’s really cool, and it allows massive about of storage in a small space, it’s costs alot to implement but because of the tape storage they essentially have “infinite” (it’s not really infinite of course but it’s a problem for next decade not this decade).