I agree with your theory, However I think the world is not ready for it. it is like the ".com" bubble, when many company lost and filed bankruptcy at the time, later one the ".com" market came back steady and succeeded.
Crypto-Currency is acting the same way, however the BitCoin market will struggle until some bank come up with a completely safe way to deal with BitCoin transactions.
Now that major banks are slowly dropping BitCoin accounts, it is now up to the private "BitCoin-only banks" to come up with that safe way and those people don't have the enough experience yet to deal with such huge amount of money and at any moments they may end up like MT GOX.
Point is: dealing with BitCoin is still very risky, it may have a bright future, some people are using some savings to invest in it hoping in the future it will lighten their lives, but average people are not ready to use BitCoin for daily transactions.
Which again also prove the point that BitCoin is being treated as metal BUT not cash money which the later was the main Point of BitCoin. Banks don't put metal (Gold) in your checking account but they put Cash money.
Banks dont need to come up with anything here. Its Bitcoins, not Bankcoin. What the hell are you even talking about that banks need to come up "with a completely safe way" and "now that major banks are slowly dropping Bitcoin accounts"?
BitCoin is supposed to be cash money for people (read the the BitCoin wiki and the example about if you go buy from a store and hand the cashier $20 or read the example about identity theft risks when you hand the waiter your credit card)
Now people used to hide their cash money before at home (mattress, pillow, safe ..etc) which no one knows how much you have and how much you spend or how much you earn.
Later on when thieves start robbing those houses, then banks came out, people started to put their cash money in banks, they gave up their anonymity and their income info ...etc in order to be safe and protect their hard earning money. Point is: Banks came for a reason!
Also how many of you check the neighborhood before renting an apartment? cause you don't want your kids be around drug dealers or arm dealers ..etc? well BitCoin world right now if full of those people which help increasing drugs and all kind of crap around where you live slowly, they found a great way to hide themselves behind BitCoin!
Majority of website now that deal with BitCoins keep you anonymous, you only need any email and a password to start buy and sell BitCoin.
If you lose your private key, you are done, your whole money is gone, no way to retrieve it, otherwise MT GOX would have been able to fix their crap. how many people here on this forum posted a thread losing their BitCoins?
Even if you back up your private key on your desktop, how many people click on different links online everyday? watch porn? or check new websites? ...etc regardless what's the reason, the average person do click on many links everyday or download some crap or even go to those file sharing websites, or download a movie or or or...etc, any of these links can have a virus with it and then you are screwed.
BitCoin is not built for an average person to deal with so far, many people don't understand how to protect their BitCoin account.
Major Big Banks don't want to handle their customers BitCoins accounts saying it is too risky, SO HOW ABOUT A NORMAL PERSON?
This private key crap and anonymity on the websites need to come to an end. Wallets and Exchange websites need to start asking (on Sign up) for the person name, Date of Birth, secret question ..etc, or Even have them Sign in with their FACEBOOK account.
THOSE PRIVATE KEYS NEED TO BE LINKED TO A PERSON INFORMATION, so in case of theft they can prove who own the money and who stole it.
Even Smart people like (danny) says that after 10 or so years when there is too many people dealing with BitCoins then they will have to change some algorithm or do this or that, proving that even if the system is secure for the time being (which is not since 100s of millions of dollars were lost so far and never recovered), still the system on the long run is not secure enough.
Until the founders or whoever find a way to link (or change) those private keys to names and address and SSN or whatever, THE SYSTEM WILL ALWAYS BE TREATED AS TOO RISKY! and it is preventing it from advancing so far, otherwise BitCoin by now (after 5 years) would have made it and became the world number currency!
As for those of you who like to avoid taxes and don't want to pay shit to the gov., well again my tax pay for the police and I like knowing that there is a policeman out there is willing to die for a motherfucker like me if someone tries to hurt me or my family!