I think building a good spreadsheet program that is both accessible and powerful is very difficult. Excel might be the most non-trivially used "programming language" in the world.
Excel is genuinely excellent. I was as big a MSFT-hater in the 90s as you are likely to be able to find, but credit where credit is due: Excel provides a level of data analysis power to a lay user that is just not available elsewhere.
Sure, tech people (cough HN readers cough) often want to trot out arguments about how "well, that sort of stuff just shouldn't be done in Excel! They should learn to use R or SQL or some other $MoreCorrectTool". That's poppycock. Excel is already on the analyst's desk. It's immensely powerful while ALSO being very accessible. Nothing else comes close.
Excel was just better by miles.