With respect to terminology, I think you're counting those on the wrong side of the ledger; I think they're liabilities, not assets.
Without an actual product, if icons, videos, etc. don't have value as fine art, they are not worth very much if they are worth anything at all. They are a sunk cost of doing business.
For the same reasons they were created instead of found and bought from some other dead project, people who need something similar will simply have it created.