there are nearly 2mln coins that have never been moved ever since being mined - most of them from pre-2011 times.
I'd say, most likely they are lost - or at least half of them.
so by these numbers, who would even care about some 500btc?
lots of coins have been lost in the past years, and many will be lost each new year.
in fact, if you think about it, getting lost some day is the final point of each bitcoin that's been or going to be mined.
it's all just a matter of time.
essentially they get to die like everything