The problem is, I think, that using SAP essentially is creating your own solution in-house... but being tied to a certain amount of structure from the start rather than being able to go off and completely do your own thing. The way it’s implemented also doesn’t generally allow for creating small solutions and building up - either the entire project succeeds several years after it’s started, or it all fails.
I once worked with an SAP consultant who had worked on SAP projects that were 100% custom development. They used it strictly as a form-building app dev platform with solid scalable transaction processing and reporting capabilities, and used zero of the pre-defined configuration or data structures. I think they had a bit of the "when your only tool is a hammer" mentality.
