So you have been mining or have purchased some coins that will fail... 
Don't worry, keep your wallet.dat file. And im sure there will be crypto collectors in 20 years time just looking to buy your wallet.dat file and revive the network with just a mobile phone. The more crap the coin and the quicker it fails, the more it will be worth.
Year 2033, your 10000 Twatcoins are now worth 100 BTC which is now worth $10,000,000
... Maybe!
Don't worry, keep your wallet.dat file. And im sure there will be crypto collectors in 20 years time just looking to buy your wallet.dat file and revive the network with just a mobile phone. The more crap the coin and the quicker it fails, the more it will be worth.
Year 2033, your 10000 Twatcoins are now worth 100 BTC which is now worth $10,000,000
... Maybe!
Only problem is that by 2033, there will be a few billion failed coins at this rate. There will always be new poop.