Anyway, second part:
https://bitinfocharts.com/top-100-richest-bitcoin-addresses.... is a good list. What you're looking for are wallets with a really early first in and no first out (or not one in a really long time).
#4 is a good one! https://bitinfocharts.com/bitcoin/address/1FeexV6bAHb8ybZjqQ... This wallet was last touched in 2011 and has $1,008,433,581.88 in it (yes, ba-ba-billion) Either this is the most disciplined investor ever or it's a lost file.
This person dropped $1,000 in 2010 on a few btc and it's now worth $245million (https://bitinfocharts.com/bitcoin/address/1PeizMg76Cf96nUQrY...) ... again, that's either super discipline or just a misplaced file.
The untouched wallets are sadly really really common, especially when you get a few pages in ... you see things like this: https://bitinfocharts.com/bitcoin/address/13DyBwhpDw6152q1dr... ... this person put in $8 (100btc), then $21 (400), then $122 (1700) and that was their july, 2010. Now it's $26.3 million.
Nobody ever believed the fantasy talk in 2010 that 1 btc was going to be worth a dollar, yet alone 12,500! Lots of people were really careless.
I'm there somewhere and have millions of dollars of bitcoins in a lost wallet. Weee, how fun!
At least that's how I'd like to think of it, otherwise some poor sod is having to think about this every single day.
With quantum computing it's expected that the ECDSA public-key cryptography used in bitcoin addresses will be broken. However, the ECDSA public key is only exposed when your first transaction out of the address is signed. If you only use addresses once (recommended practice), an attacker would have to break your private key faster than it takes for your transaction to propagate to the entire network in order to steal your coins. It would take a long time between the first cracking of ECDSA to nearly instantly being able to crack it. For example, the first publicly-disclosed attack on SHA1 took 110 GPU-years.
If the accounts listed by the OP have sent transactions in the past and reused addresses (which was common back in 2010/11), it's possible the private keys can be bruteforced in the future.
If not, we don't know the ECDSA public key for the address. Bruteforcing it gets a LOT harder--but never say never.
A lot of people track and watch these wallets to see if anything moves, it would cause a lot of panic if these lost coins started moving.
Ie, if one day Coinbase says something like, "sorry, we lost the password to one of our internal coin wallets due to technical error, and your 5.1 bitcoins are lost."
I bet there's some clause in their terms that tries to shield them from this, but wonder how enforceable it would be.
Ie, a regular bank presumably couldn't just say, "sorry we lost your $50k deposit due to technical error". They'd be liable.
Ie, there's a small chance of a user screwing up. And since there's no recourse, always a perpetual small chance of someone losing their bitcoins.
Maybe Poissonian?
I think you got your terms mixed up.
He is not alone in this.
(Sounds like he went to a good party, the night was long and when he finally got back home he realized he didn't have his hard drive on him anymore.)
Now a pen-drive maybe, but that wouldn't be the place to store my wallet anyway.
Ah well, 20 grand lost in limbo.
Bitcoin was supposed to be slightly inflationary, due to mining. But if a sufficient fraction is lost every year due to hardware failures and forgotten passwords, it will end up being deflationary. Someday (around log(1e6)/log(1+x) years from now, where x is the fraction lost every year), there'll be only 21 bitcoins left in the world, trading either at 0 or a number with 3 or 4 commas.
[edit: fixed in/de-flation mixup]