You're not a coward, you're facing the doubt that everyone else does. However, it is unhealthy to think that the SaaS you dreamed up will be successful, when so many others have failed...that realization that you've had, that there are advantages to undertaking projects that fail...that's worth holding on too...as while you may not frequently succeed at first, you can still keep learning the skills from building the failures that will be needed for a success.

Also worth realizing that the success of a project is not based purely on hard work and skill. A great amount of luck is involved.