A currency for the planet earth has to be robust against failure. Bitcoin happens to depend on certain specific cryptographic and hashing algorithms. These are believed to be secure today, but there is a chance that a hack is found or a rainbow table is developed.
If someone hacks the hashing algorithm and can produce blocks extremely rapidly, they could take control of the blockchain, at least until either their hack became widely known or all the miners switched to a different hashing algorithm. Far worse, if someone hacked the public key algorithm, it would be a race against time to move your bitcoins to another currency or have them stolen.
Will this be a problem for bitcoin? I don't think so... Don't use bitcoin for your retirement fund.
One could imagine a cryptocurrency that uses multiple public key and hashing algorithms simultaneously, and has the ability to add new cryptographic algorithms if one is ever broken. This would obviously be more secure than bitcoin, but slower and stuff.
Question: Is the probability that a cryptographic algorithm used by Bitcoin gets hacked greater or smaller than the probability that a friggin huge gold deposit is found, rendering gold worthless?
you should search a little about all the math behind these algorithms...
all the time and the energy that would be needed to MAYBE some day achieve that.
Should every one deposit all their money and dreams in bitcoin? of course not, diversification is the word in this market. Bitcoin is my main investment, but for sure it isnt the only one.