Excel is used to store data, visualise data, manipulate data, write 'code', and share artifacts (worksheets). Writing software is better for all of these things, but normies weren't able to write software themselves. Now they can.

I also reject the premise that excel is simpler. Building a spreadsheet of any real complexity is a genuinely learned skill. It's hard. Often you are wrangling with the limitations of excel. Version control, tests, permissioning etc is poor in excel but a solved problem in software.