[mjn]

On #2, a colleague of mine has a hypothesis that that's a primary reason a lot of smaller enterprises (on the threshold of enterprisey) buy ERPs: it tells them what they should be keeping track of and how, along with providing the tool to do it. When small companies grow large quickly they often end up being very unsure of how to structure their processes and accounting, and having a built-in solution for "this is how companies in field X do things" is appealing. So it's not only that they worry about the risk of building an in-house solution, but they also worry they wouldn't even know what should go in the solution! Buying SAP not only gives them the software, but a template for how to structure their business's processes.

In a way it's a little like adopting git and a particular git workflow. Adopting the workflow can be the really valuable part, especially if you had no idea how to structure a workflow in the company previously. The tool is secondary, and just helps structure the workflow. Seen that way, implementing SAP is sort of like buying a default-business-process template, along with some enabling software. (On the other hand, it does run the risk of producing some cargo-cult business practices. If businesses structure their processes to fit SAP, rather than vice-versa, it's not necessarily the case that anyone is checking whether these processes still make sense.)