Hey, I know this is probably was considered before, but why not make coins have limited age before they return to coinbase? Say if coins have not been moved for 8 years it "returns" to coinbase (i.e. become unspent) and become minable. This way coins that was unspent for certain amount of time will eventually reenter circulation, we can discontinue block reward halving practice, eliminate satoshi's stash (or force him to reveal himself) and reintroduce destroyed funds to the market. This will also limit blockchain size so we would be able to use much larger blocks, allowing much more tx/second since blockchain size will be capped. More I think of it, better it seems from scaling perspective.

I know I probably missing some significant downsides but I can't see something that can't be compensated.

I see coins aging could be a viable on-chain scaling solution (scenario where coins that was not been moved for full halving period will automatically return to coinbase). If this will be the case - full nodes will only require to store blockchain for the past halving period since anything that remained unspent will transfer to the coinbase. This is drastic and, perhaps, cruel measure to take but that will also solve satoshi't billions, burned and lost coins problem.

Here are a few of the ideas which I think would be most interesting to see in an altcoin. A few of these things may be possible as hardforking changes in Bitcoin too but some represent different security and economic tradeoffs and I don't think those could be ethically imposed on Bitcoin even if a simple majority of users wanted them (as they'd be forced onto the people who don't want them).

(Some of these ideas are mine, some are from other people, some are old and obvious)

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• UTXO aging
  
  • Abandoned UTXO should be forgotten and become unspendable.
  • Demurrage is one possible construction for this, but its economically and educationally complicated. Simpler would just be having a long but finite maximum. Unspendable coins could vanish forever, or be returned to mining— but returning the coins to mining is economically distorting and risks creating weird incentives ("I won't mine your txn because I want to collect its inputs as fees once you've been successfully denied")
  • ATTENTION MORONS: THIS CANNOT BE DONE WITH BITCOIN. SEE THE LARGE BOLD TEXT AT THE TOP.

[...]

Since this will never happen in Bitcoin, I suggest that you should go put all your money in Freicoin (FRC), a coin created by people who make economic arguments for demurrage.  Freicoin is currently ranked #675 on coinmarketcap.com, with a current market cap of $485,681 (27 BTC).  (Current Bitcoin market cap: $307,305,229,550.)  The idea that you should need to spend your money to not lose it—well, that idea is exactly as popular as it should be.

[...]

Do you know what happened to Satoshi and his private keys?  I hate it when I see people salivating over Satoshi’s coins, declaring them a “problem”.  What if he laser-engraved the private keys in corrosion-resistant nickel alloy plates and secreted them in a treasure cave for the benefit of his posterity, the future Nakamoto Royal Line?  What if he’s still around, lurking in the forum or posting under another nym?

More generally, who the hell are you to find a “problem” in the unknown numbers of people who have simply made long-term plans?  As opposed to children, adults measure “long-term” starting in decades.  There are people out there who have moved a portion of their assets into a Bitcoin cold wallet, and written the BIP39 seed phrase therefor into a sealed Last Will and Testament.  What makes you think you can steal their children’s inheritance?[/li][/list]

If you think the foregoing comes off as harsh, stop and consider that Bitcoin’s value derives from its promise of safe, secure, stable currency in which everybody can participate without anybody’s permission, according to a set of rules declared in advance and known fairly to all.  Any change to those fundamental rules which seized away people’s coins would instantly destroy Bitcoin altogether—which is why it will never happen.  No, I haven’t been harsh; not by half.

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