Why not? There's plenty of other dead currencies that can't be practically exchanged for money. Or if they are, it's because they're interesting looking enough to attract collectors, which is not something that could be said for Bitcoins.

Non-negligible value of BTC also depends on constant investment of electricity in mining more Bitcoins and companies dedicating resources to maintaining payment/exchange infrastructure

This is a really interesting point, and I could see the parallel with currencies such as Confederate or Deseret money, or pre-Euro/pre-WWII currencies, but even those have insane values now that they are defunct. Look at the price of this old Utah territory money that existed as long as their own language (not very long) http://www.rustcoin.com/Deseret-Currency/