Picky: 20 years ago was early 1992, and Quattro Pro was only 2 years old then. QP came out shortly after Lotus won their look-and-feel lawsuit against Mosaic and PSI (I had been a VP-Planner user along with 1-2-3 at work).
I can understand the ribbon as a reconceived menu. MSFT reorganized Excel's menu between Excel 4 and Excel 5. Necessary in part due to VBA newly included in Excel 5. However, MSFT provided an Excel 4 menu as an option in Excel 5. I don't recall whether that went away in Excel 97 or 2000.
What I can't accept is that the ribbon is a useful replacement for toolbars, which could be docked on any side of Excel's application window or floating on top of document windows. In addition to placement flexibility, toolbars were much easier to program, and could be programmed using VBA. I have the impression Office 2007 and Vista were rushed to market as a lesser evil than waiting another year to get them right. Ditto more strongly Excel 2008, the Mac version so rushed to market MSFT had to drop VBA support only to bring it back in Excel 2011.
I'm glad I went straight from Excel 2003 to 2010. I couldn't have stomached Excel 2007. Excel 2010 still has a ribbon, but at least it can be customized. Not that I've done so. I've heavily customized my QAT, and haven't used the ribbon for months. If there were only some way to keep the QAT but dump the ribbon (not just minimize it).