I'd say they've perfected their factory management skills in churning out the series/movies of the franchise from their fine-tuned, optimized production lines, which I think could be fully automated & run by more intelligent software in due course.
You jest (I think), but what I meant was simply that Toei truly learned how to make good classic, feel-good magical girl anime (plural).
Like, we have Sailor Moon, or Madoka, Nanoha, etc., but when it comes to genre itself, Precure is the first thing that people think of when someone says magical girl show, and in most cases Precure series is used as a basis for parodies, or simiar stuff.
Compare visuals from the first Precure series to the series in last few years, and even if you don't like stories, or characters themselves, you can still notice that Toei developed their animation for that kind of anime, and it looks great when they want it.
I am convinced that if Toei decided to make another Sailor Moon anime, but in similar fashion to 90s series, with a lot of fillers, additional character development, more slice of life parts where we get to know them better in private life, and without 1:1 adaptation approach, animated by people who work on Precure, it would end up with them making a rather memorable modern classic.