That's also why it's usually a multi-year project to introduce SAP systems at an existing company. The hard part is not installing the software (though I'm not saying it's always easy either). The hard part is getting all layers of the company to change away from their pre-existing, sometimes nonsensical processes.
(Disclosure: I work at SAP, though not on customer-facing software.)
(Disclosure: I work at SAP, though not on customer-facing software.)