People are allowed to be selective about how they make things available, and they're allowed to stop putting the effort in to keep them available without forfeiting their rights. Again: we aren't entitled to access this stuff, except by contract, which spells out our remedies when they exist.
For precisely the same reason people believe tax dollars should go towards enforcing the GPL. You're welcome to disagree, but not to withhold your tax dollars when you fall into the minority.
You're just regurgitating what the current laws state. The whole point of this discussion is that said current laws lead to most media effectively becoming lost after a certain period of time and this is a problem, so the law should be changed.
And to be even more clear: The constitution has to explicitly permit copyright because otherwise it would be an unconstitutional limitation of people's rights, most importantely of free speech.
