We've no idea whether 4 million Bitcoin is really lost. It's only rough estimation and we've no idea if the lost coin is actually owned by long term HODLer.
Lost bitcoins
According to an article made by Fortune, there are around 4 million lost bitcoins forever. Chainalysis claims that 17%-25% of Bitcoins total supply has been lost forever due to original coins minted and early investors not paying attention to them, and transactions mismanaged. It is claimed that Satoshi Nakamoto owns around 1 million BTCs but no one can back that claim and they havent been in movement for years, maybe they are held as reserve when we mine all bitcoins? Anywho, according to the research there are $5-$20 Billion worths of bitcoins lost forever.
What if we could make a new bitcoin while containing all the original aspects and not hard forking it?
There are many major problem such as :
1. How do you determine which coin is lost without rely on centralized analysis
2. It's impossible to do your idea without hard-fork since the only way to move Bitcoin is by knowing it's private key.
Token Swap
Tokens that use Ethereums ERC20 standard and wanted to leave the network for their main network have used the token swap method. This method consists of migrating old tokens into the new protocol leaving the old ones behind useless. Tron, EOS, and Vechain have migrated all their tokens into the new protocol consisting billion of dollars in movement. This process is easier said than done, but its definitely possible.
So basically move to entirely new Blockchain and delete/remove all transaction/address history?
This could weaken Bitcoin security and swap process is dangerous unless they use completely decentralized method.
Bitcoin token swap
What if we would migrate all the bitcoins in circulation, keep all the components but take recreate all the lost bitcoins and set them aside for mining rewards, social impacts, or anything with a decentralized community driven vote. The scarcity of bitcoin will stay intact as there will be always 21 million bitcoins, but the mining reward can be increased to incentive more miners to join the network.
If the way to determine "lost" bitcoin is just by check last transaction date to spend the coins, then HODLers would be forced to move their coins regularly.
What other solutions or uses do you see good fit and fair for the 4 million Bitcoins? Let me know what you think, we are all trying to make the bitcoin network more reliable for different uses such as a store of value, currency, cross border transactions, investment tool etc.
There aren't any way fit or fair way for the "lost" Bitcoins and IMO we should left it alone.