After a lot of thought, and watching my sales, I have decided to unpublish my stories from Smashwords. I have on record exactly 2 sales there. It's just not worth it.
I had originally removed my stories from Amazon's KDP Select program, since it forbids you from publishing elsewhere, just so I could publish there. I figured it might be an added market for my stories. But, the sales don't lie. I make a handful of sales each month at Amazon, so why not just stay with them?
So, I have re-enrolled all of my stories in KDP. At this point, it's worth it to try that again. It can't hurt anything.