And there is the key.
Do you actually want more sustain?
If you are often playing melodically and lyrically on your bass, maybe. But I don't tend to play that way, nor do most electric bassists IME.
I don't. I can't think of an electric bass part I've ever been called on to play, or composed myself, in which I felt that a lack of sustain was a problem. It's far more often that I take steps in my playing (and setup) to get a note that inherently has shorter sustain. Right hand muting. Left hand muting. Foam or felt mufflers on the strings. Tools I use every time I pick up a bass. NEVER have I though to myself, "This note is too damned short. What can I do to make it longer?"
The quest for sustain on an instrument that is the lungs of the rhythm section is largely a technical quest IME; it has little real-world application.