I think key part is "for duration of project". Savings, if successful, then come for the lifetime of erp.
One thing I've seen frequently is treating erp implementation as IT project. I'm a technical team member doing erp implementations for last 25 years (not sap) but I'll freely admit erp implementation is not about me or technology. It's primarily a business transformation project. You need those erp business process experts to guide and customize, AND you need thorough willingness to change your internal processes to fit the industry best practices you're buying. "successful erp project" empathically does not mean "installed it and it runs". It means thorough and detailed understanding of requirements, mapping to new processes, customization where absolutely positively necessary, substantial and organized and embraced business transformation, extensive training, and thorough testing including user acceptance testing.
If you think is erp as something you just install and life will be the same but magically better, you're gonna fail hard. Missed requirements and edge cases, and or significant internal resistance to change, are frequent challenges.
Because SAP is what most other companies in the sector use and because there are few alternatives. And because everyone else is m uses it, it must be good. Right? Right?!
Also, because leading employees usually have no idea about the intricacies of the "old" system and think it's easily replaceable with a solution from the shelf.
