ERPs are a great example. but I don't necessarily agree with your view that a large enterprise's existing workflow is superior. My take:
Most large enterprises have workflows which could be vastly improved by automation of ANY kind, even one that is imposed by a minimally customized ERP. ERP implementations are most successful, on both an ROI front as well as success in implementation, when they are brought in and the existing workflow, at a high level, is redesigned to fit the tool. Why?
The other path is chaos, because you are essentially asking people whose jobs revolve around doing things manually to "build their own replacement." A simple way of putting it is getting the assembly-line workers to have input on a new, highly automated assemblyline. They don't want the robots to do their jobs for them. Instead they will all insist on the value of their interaction in the process, and the robots will simply be tasked with helping them do their job instead of simply replacing them.
When ERPs succeed, they lead to lots of admin people getting laid off or reassigned. These are the same people that have to be consulted if you want to customize them for a company's existing workflow. They fight tooth and nail to keep everything the same as it was.