The many years of "yea we'll add that feature" usually means a long lasting enterprise product ends up as a customize-able workflow tool with a customize-able rules engine that stores data as an EAV. It may be slow, but throw enough servers at it, and it can handle your workload. Then you just have presets for each market that you can pre-load the rules and workflows, and data if required. It's absolutely crazy. You have to fight to keep your product from turning into an XML parser.