Sadly because the industry actively fights against it, and people can be punished for it.
Also "sadly" because it's not exactly a dependable process -- we're depending on people to spontaneously choose to preserve / share media widely enough there will be decent copies when/if they go out of "legitimate" circulation.
It'd be better if archiving & preserving copies were a mandatory step to being awarded copyright protection. (Which would not displace filesharing, of course...)
Another sad thing is the mentality of IP rightsholders. For abandoned songs/movies/works that don't make any money anymore, they'd rather expend the cost/effort to destroy them than allow them to be distributed for free, even though destroying them is likely more expensive. Totally malicious. Reminds me of grocery stores that throw out food at the end of the day and spend effort guarding the dumpsters so nobody gets food for free.
Also "sadly" because it's not exactly a dependable process -- we're depending on people to spontaneously choose to preserve / share media widely enough there will be decent copies when/if they go out of "legitimate" circulation.
It'd be better if archiving & preserving copies were a mandatory step to being awarded copyright protection. (Which would not displace filesharing, of course...)