When you think about why you launched the business and what your expectations were, you will likely find that it wasn't mediocrity that you had in mind. So, by that definition, mediocrity is failure.

But, it can actually be worse than failure if you let it keep you in limbo too long, thus preventing you from reaching your true potential or achieving your mission elsewhere.

And, if you find that it is not enjoyable or actually painful to continue, then it can be far worse.