There are only two things I've seen that ever came close to actual "spreadsheet killers" - MS Access and computational notebooks (Jupyter, Observable webapp). And it so happens that both are very similar in principle to Excel spreadsheets. They're optimized for certain paradigm (reactive cells, RDBMS CRUD, reactive cells accepting code and outputting rich content), but otherwise don't constrain you - instead, they invite you to build your thing incrementally,
figuring your problem out as you build the solution, with full visibility into intermediate states.
The only way AI has a chance of killing spreadsheets is if it replaces a Real Programmers, by becoming a tool that lets anyone interactively build arbitrary apps, for free (on the margin), with near zero turnaround.