Still, I guess more MS Office users will have used the new interface for longer than the old one than vice versa (I googled for data, but couldn’t find numbers)
It even wouldn’t fully surprise me if, a few years from now, there were more MS Office users who never used the pre-ribbon interface than who had used it.
Office 95: https://i0.wp.com/isoriver.com/wp-content/uploads/2020/01/06...
Office 2003: https://imag.malavida.com/mvimgbig/download-fs/office-2003-s...
Honestly even Excel 3.0 (1990) doesn't look that disimilar (https://goughlui.com/wp-content/uploads/2014/05/about-excel....)
So that's 17 years for toolbars vs 13 for ribbon