The clause "it's absolutely necessary for all but the simplest toy examples" is what I was disagreeing with. But I wouldn't be surprised to hear that visicalc adopted one as soon as it was technically feasible in later versions.

A still-very-common use case for spreadsheets is just to manage lists of things. For these, there are no formulas or dependencies at all. Another is simple totals of columns of numbers.

There are many common spreadsheet use cases that don't involve complicated dependency trees.