I am curious why the author suggests programming spreadsheets is "hard" but programming an operating system isn't. Arguably, all you're doing in a spreadsheet i

I am curious why the author suggests programming spreadsheets is "hard" but programming an operating system isn't. Arguably, all you're doing in a spreadsheet is building a dependency graph of nodes, then re-rendering them when an input changes. It's about as complex as building your own React.