😁
In the example I used above, although I mention the Smart Playlist emptying out, my timings were designed to prevent that happening. But suppose this is really, really the desired effect?
How about the following then? (not quite so fantastic, but...)
In the regular Playlist of 3,321 songs, note the minimum number of Plays the songs have had. (You can display the Plays column in the view for an individual Playlist, in the iTunes Library.) Suppose some have been played many times, others not so many and some two or three times. A few songs have been played only once, some have never been played.
It's possible to create a different Smart Playlist that once again, looks at the first regular Playlist. But this time, the second rule is Plays is less than 3. Any song that has been played once, twice, or never at all will be in this new Smart Playlist. Songs that have been played three or more times will not be in it.
When the Smart Playlist empties out, because every song in the Regular Playlist has now been played at least three times, simply change the Plays is less than to 4, or 6, or 9 - whichever number you choose. Obviously, in this example, if the number is set too high, then a song can potentially be played more than once before it's excluded, without every other song being played. But I hope you get the idea.
One of my Smart Playlists looks at several other Smart Playlists, each with a different exclusion time. Favourite songs come back into the master list sooner than less favourite songs. In addition, the (master) Smart Playlist watches one extra Smart Playlist, that is set to Plays is less than 1 and limit list to xx songs. That's to chuck in a few songs that I have never played.
It's the Magic List.