When you add sufficient rules to spreadsheets to make them more well-behaved, they just become UIs for SQL tables stored in a SQL database. Instead of autofilling formulas they just become generated columns. Pivot tables are views or materialized views with GROUP BY.

Unfortunately I’ve never found a SQL UI tool that optimizes for fast data entry in interactive use. Most UI don’t even allow the use of arrow keys to move between cells.

I tried working on this idea at one point. My conclusion is that doing it sensibly ends up removing all the advantages of spreadsheets which makes them so widespread (as the beginning of this article discusses so well).