In a sense, I've intended for these projects to fail.
I throw something out there, see if it sticks, and is worth pursuing. Most things aren't worth pursuing. I get bored, distracted, and find something else "shiny" to do for a while. That "shiny" thing is usually my actual business. Sometimes one of my projects succeeds, and becomes an "actual" business. Other times, it sort-of hangs on for years on auto-pilot. Sometimes one of those auto-pilot things takes off. If not, that's fine.
Many of these projects can be thought of like R&D; most R&D, really, is a dead end, or something that quietly gets folded into a pre-existing project, or just gets turned into "useful knowledge" for the next bit of research.