So Boeing thought that a possibly cheaper software solution would work, increasing shareholders returns, sadly the software solution was ever so slightly oversold. End result redesign the area around the boom to accommodate the hydraulic system, lots more work for the production planners etc.
Was the software solution by itself ever tried on the KC-10, as either a proposed improvement to the design or as a test for the KC-46A, as a risk mitigation trial? I think that we know the answer.
Who signed off the design for the boom with just the fly by wire software, was it Boeing or the USAF?