I've spent the better part of this decade interviewing IT security experts, vendors, chief information security officers, and other security mangers in just about every industry. Generally -- and I stress *generally* (as there are always exceptions) -- retailers, manufacturers, and heath care providers have tended to have the least mature security programs in place. Not true in every case, but I found it to be true often enough to see a trend.
Prior to the adoption of PCI DSS several years ago, online retailers and brick-and-mortar retailers barely paid attention to IT security. Trust me, in 2003, when it came to a Top 10 list of the most pressing IT objectives for most merchants, IT security ranked around 580th. They probably spent more time evaluating stationery than how to secure their databases, Web applications, and VPNs. So when you see retail IT managers arguing over whether they should install a Web Application Firewall, or conduct application security vulnerability assessments, or even do both, you can thank PCI DSS to a large degree.
PCI DSS has done more to raise security awareness among retailers than anything else I can think of. Even the torrent of breaches earlier this decade. And, while I can't quantitatively prove it, PCI DSS has most certainly raised the security of the retail industry, in general.
The unfortunate breaches of Hannaford Bros. Co, and more recently Heartland Payment Systems, which were both PCI compliant, doesn't make PCI DSS either irrelevant, obsolete, or worthless. Whoever thought PCI DSS would eliminate data breaches in retailers should probably make sure they don't work in IT, and definitely make sure they don't work in IT security. Its goal was to raise security among retailers and merchants, and to a large degree its been a success.
This standard isn't perfect, not by a long shot. The standard won't eliminate security breaches -- and no one said it would. But the standard has increased the security of many retailers, and probably stopped quite a few breaches along the way.
Do we talk about the "failure" of law enforcement when someone commits a crime? Do we talk of the irrelevance of physical security when banks are robbed? Do we talk about how "worthless" the military is after a lost battle or two? Do we talk about how eating healthily and exercising is such a waste when falling ill?
No, intelligent people do not do those things.
The battle against cybercrime is like any other long-term fight, and once in awhile companies that strive to do everything right are going to find themselves breached. It's the nature of this beast, not the fault of PCI DSS.