I've abandoned manuscripts here and there. Some part way through and others after a few rewrites.
Generally I keep them in one form or another as one never knows when a character, turn of phrase, or even a story bit will come in handy.
You can bet I am grateful I do it.
Yesterday such a thing happened.
I clicked on an abandoned manuscript and ended up reading a recast excerpt from a different manuscript. I'd made it fit with very few changes.
This particular manuscript still needs to rest. It may never see the light of day. But the excerpt might.
Either I can recast the original or recast this recast and make it a standalone story.
In fact, I've left myself a computer sticky note to do just exactly that.
I'm eager to get at it and will know shortly if it is workable. Whether it is or not does not matter right now. What matters is I have the material to play with and for that I am grateful.