Right... it’s a solution for folks who have this existing knowledge. The aim I guess is to transition folks to non-keyboard devices for navigating the UI...
Menus in Windows had already lost the accelerator key decorations by default well before the Ribbon (by almost a decade at that point). The Ribbon didn't cause the loss of always visible accelerator key UI, the Ribbon was built when accelerator key UI was already lost for being too noisy.