Plenty of other programs that are great for data manipulation. They are dead in the water without office due to vendor lock-in and not willing to spend the time switching to a different system.
It's one thing switching internally, but if you need to deal with customers/suppliers/authorities etc who send or receive Excel format spreadsheets, it's kind of hard to switch. Paying a few hundred dollars a year, for a business, is a small price to pay to have things work relatively seamlessly (compared to alternatives such as LibreOffice).
Also I think you are underestimating what people use Excel for. I've seen companies uses macros, tens of tabs, and basically build the software that runs their business in Excel. It's not just a simple spreadsheet.
