How could they calculate this if they weren't tracking it?

The cost would need to included not just development hours that have gone into creating and maintaining the system, but hours of other employee's used for the project. Also the servers, the network, buildings, etc.

If there were forced to calculate this number, it wouldn't surprise me if they were able to do so in a manner that shows they lose money. At best they could be forced to track the cost going forward using a third party auditor.