I never gave it a lot of thought since the last time I used SAP was in a company where we converted from MRP to SAP and it actually went really well. At the time our switchover was the greatest success story for SAP switch overs. It took us something like 2 years to do it, but the new system (SAP) was much better once you forgot everything you knew before in MRP.
SAP basically runs the company I work at now, except for some legacy systems we used for manufacturing traceability (I am in manufacturing engineering on the electrical side). Scuttlebutt is that we will be going to SAP for all of our transactions on the production floor, so I will have to re-learn how to use the system because it has been about a decade since I last used it.
So I guess to answer your question; I think they make too much at more than twice my salary, so I would say it’s worth more on the order of perhaps 80-90K to be a SAP expert (meaning you can program and manipulate the system).
How any executive could look at that outrageously defective and hideous interface, that plainly showed the incompetence of all involved with it, and say "sure let's pay a few million up front and a few million a year more a year for that" is way beyond me.