Like I said, IGNORING THE SYSTEM. You're talking about a specific program that is cracking a password file. Not to mention, a program like that requires access to the machine in the first place, which would probably make it a pointless endeavor to recover passwords, you already have access to the data.
There are offline password attacks that do not depend on prior access to the system. There have also been ways to use unprivileged access to obtain hashed passwords, which can lead to successful privilege escalation attacks.
We could go on all day about specific circumstances where this works, and that doesn't. In the end, it doesn't help at all because most people will tend to form the opinion that it doesn't matter and they will keep using weak passwords.
That's where policy, enforcement, security education and token-based authentication can help. I have customers who use and enforce strong password policies. In many cases it took significant effort to implement due to end-user resistance.
You want a specific example where a 6 character password will work? Try and crack 256 (try 128 for that matter) bit AES where the key was hashed from a 6 character password. Never going to happen.
Cracking AES is exceptionally difficult and expensive, and likely to be infeasible for some time to come. But we weren't talking about encryption keys, we were talking about account passwords. These are frequently stored as hashes. While there are no hash-reversal attacks that I'm aware of, there are some good attack modalities. These attacks work a lot better with six character passwords than they do with longer passwords of roughly equivalent complexity.
In the end, if you want true data security, authentication to prevent access to the system is not the answer. Encryption is the only thing that will prevent access to your data, and even that depends on the implementation of the algorithm itself (plenty of examples of encryption software with holes).
Encryption plays a critical part of information security in many systems. As you say, most successful attacks against encryption work because of weak implementation rather than weak encryption (WEP being a notable counterexample).
Unfortunately encryption by itself does not result in secure systems. While I'd put software and configuration vulnerabilities ahead of authentication issues, weak authentication continues to pose a significant threat to information security. Data secured by strong encryption but weak authentication can be quite vulnerable.