I am not sure of other programs doing this type of effect myself, I think if I was looking to do this, I might use a recording method... at least in my head it makes sense.
I would basically set up windows and the Music Maker to record from the internal sound source "What You Hear" or "Stereo Mix" then playback the part I want to have this effect added and use the virtual control surface of the tempo, time-stretch, pitch shift ...live while recording that at the same time. But, I have never needed to do this for my recordings, so there might be an easier way, I am just not aware of it.
Otherwise, I would be using the method you know, which is placing splits each time thus allowing a gradual increase or decrease.
But I think this is something noteworthy for a request in future programs, if possible... maybe as an effect curve.