The learning curve may be a few years, and its soul crushingly boring. But once you're qualified and competent at it, you just put on a suit and take your trolley from one large business to the other, whilst charging 200€+ per hour. You don't have to actually implement anything, only advise.
It's like the modern COBOL. Every sizable business runs on SAP, and it's complicated. The demand for high-end consultants in this space has been there for 20 years and won't go away.
As old man I will express caution that money isn't everything. Personally, I'd prefer digging holes into the ground in the streaming rain as a job over anything SAP.