"Grit" — A prerequisite for success?

This article makes some good points. The book it cites sounds interesting. But it also lacks some nuance:

Whether you need to specialise early to be a success varies greatly by field. It's hard to become a world-class violinist or gymnast unless you do serious training from a very early age. The same is NOT true for, e.g., a law professor or a scientist.
Whether "grit" succeeds in making you a success in a given activity or field depends in significant part on whether you like the activity and have an affinity for it. A person who dislikes playing the violin (as I did when I took lessons) is unlikely to become a successful violinist (even if, unlike me, they have the talent for it).
It is indeed important to know when to quit, but also important to know not to quit too early or at the first sign of resistance. Whether quitting makes sense depends on a variety of factors (including what else you can be doing with your time). It's not always easy to say when "don't be a quitter" is better advice than "don't reinforce failure."

faith in self is more important than grit.

then come being honest with self, and feeling out different things.

i know that if my heart is not into it, I will not stick with it.. find what you love to do. it may not be the most profitable, but it will be the most valuable long term, to your happiness, and the joy you feel.

so many think money will bring them happiness, but it is the joy along the way that we truly seek. and there is no happy ending to and unhappy journey, as seen by the many a miser that died rich beyond belief.

it also seems true that it must be done in the right way, or else you will think yourself a fraud for all your days. i can not think of a worse fate.

or the other side, if you steal/cheat to get your dream you will find yourself ever afraid that you will have it taken from you in the same manner you got it, or be found out and horribly killed.

but grit... well i have a bad taste in my mouth after watching that movie 'true grit'.. which the girl basically traded her arm for the death of a worthless man.

but in the sense you are saying it, I say Faith in self, if the dream is true, then following your dream with determination can be a good thing, because there are many that have given up on life/their dreams.. and it pains them to think they gave up, they'd rather it was impossible so they can feel better about their choices, so then we must be careful who we take advice from.