An economic loss to who?
If you need to ask that, you don't understand the problem. Try reading up on the broken window fallacy.
If you need to ask that, perhaps you need to read up on this.
Obviously it is a small economical loss to the merchant, but it prevents much larger losses by others. This is called an externality.
PCI may be a loss for the merchant (cost of doing business), but an overall gain if it prevents loss to the card brands or consumers.
This has driven down crime in the UK with their Chip and PIN system.
Here in the states, the industry is pushing ahead with encrypting magnetic stripe readers, but that still does not protect you if the attacker taps into the read head before it is encrypted.
I saw a device inside a gas pump in California two years ago. It was the size of a pack of gum, and made specifically to plug into the pump's cables. Small ICs, a pro job.
And it's quite accurate: nothing can guarantee security.
FTFY. There is no perfect security. I don't know anyone that says PCI compliance guarantees you are secure. But it is an indication of the controls you have in place protecting cardholder data.
For instance, hiring a licensed, bonded plumber doesn't guarantee they won't screw something up. But your chances of a good outcome are a lot better.
Hotels are tired of getting ripped off. I checked into a hotel and they had towels from my house. -- Mark Guido