"Middleware" is IT-speak for "we've got this closed-source thing over there, and it doesn't talk at all to this closed-source thing over here, and we have no idea what their data formats or wire formats are but we've spent scads of money on both of them and now we need them to talk to each other, so can you please figure out how to make that work?

It's the user tax on closed formats and closed source, basically.