Anyway, the point is surely that if LibreOffice really wants to attract users from Microsoft Office, then it should do everything possible to optimise that transition?

Offering the option of a UI mimicking the familiar MS Office layout is not a difficult engineering problem. And if it makes users significantly more likely to switch, it should be a high priority to implement.

Honestly, at this stage, thinking of Gimp, FreeCAD, LibreOffice, and Blender, it’s as though there’s a weird group psychology deliberately against offering even decent (let along best-in-class) UIs in the open source world. These are all apps with excellent fundamental underlying engines/tech which are handicapped hugely by their UI/UX. (Yes I know some of these have improved in recent years, but only after far longer without improvements.)