There is a difference between building or inventing something that really works, and getting a large percentage of the population to actually adopt it. You could say the thing you worked on 'didn't fail' if it really did what you designed it to do; even though almost no one recognized its value and put it to use improving their life, even in some small way.

History is full of very useful devices that only improved the lives of a few people; while also full of mediocre devices that were widely adopted due to very good marketing.