Microsoft did usability studies on real people to determine the ribbon interface is better. This is back in the days when software companies cared about objectively verifiable results.

Only no, it’s not and everyone reviled it when it came out but we’ve been stuck with it ever since.

MS may have done usability studies earlier (say, when they cared about dethroning Lotus 123 and WordPerfect) but that war was long won when the ribbon UI came out, by then they only cared about milking the cash cow.