Yes, I think it's the no 1 reason I saw solopreneneur friends fail. Most are just not willing to put the hours in. I see that people really like to dream and make big plans but sitting down consistently after work each day and actually working on all the mundane small things is a necessity many are not willing to do. The idea/business might still fail but without actually doing anything you have lost already.
Entrepreneurship is as glamorous as being a doctor at the emergency room.