Just thought I'd pose an intriguing question about old BTC addresses and what happens to them?
Supposing that someone, after a crash and losing their old BTC client and being unable to restore this goes and downloads another client, gets another address and starts sending to this client. Then one day, they accidentally send BTC to the old address and realise their mistake - where has their BTC just gone? i.e. down the drain or to another person? Is there someone somewhere profiteering somehow?
So what happens to the old address?
So somehow because the transaction has 'gone through', presumably there is only a record of it that can be accessed via block explorer and the client having failed to receive, the BTC has just 'disappeared' down a black hole?
There may be a more fool proof user friendly system developed in the future. At least I would hope so, a tighter built in back up system, maybe it will all be cloud based. You can already use wallets online, it's just whether you trust them or not!
If BTC is to be widely used, a user-friendly method is an absolute requirement. Tech geeks live in a bubble where they don't even NOTICE that they're doing things the average user would take weeks/months to learn to be comfortable with.
Personally I think the concern over "trust", with respect to your wallet.dat backup, is somewhat overblown. Yes, it needs to be held secure. However, most security breaches occur not because of a super hacker who figures out all your private keys and takes over your life or somehow knows YOUR WALLET IS CONNECTED TO TEH INTERTUBES RIGHT NAO!!!!oneeleventyexclamation. Most security breaches arise from users giving that information away (i.e. social engineering), or via physical access to the secured resource (someone gave away a URL or a password).
The same issue arises with banks, top secret information, etc. The solutions have not been to deny connected access to the data, it has been to put processes in place to ensure users don't give away information and to prevent physical access to it. A bank can't protect you from someone finding the slip of paper where you wrote down your ATM pin and subsequently finding your ATM card.
What I'm getting at is - a user-friendly method of doing anything always sacrifices some measure of security. I would contend that that is actually fine with respect to wallet.dat. An encyrpted cloud storage model with a sufficiently complex password should be more than enough security for this and would be shockingly easy to implement.
Which gives me an idea...
Finally - with regard to losing physical money. That's a different beast. Even if you drop a gold coin into the middle of the Nile, some enterprising individual could still scuba dive down there and retrieve it. It isn't lost forever. When a wallet.dat is permanently lost, along with its private keys, the BTC are gone forever. Most people have neither the expertise nor the inclination to attempt a HDD recovery and most users don't even keep meaningful backups. While the rest of you cheer because your BTC's are suddenly worth a tiny fraction more, the person who lost them (read: average user) will forever hate the system and tell his friends to avoid it. The success of BTC will depend on more than tech geeks using it. If that is to happen, money can't be able to be "lost" in this way.