But, how the character is perceived in-world is informed by how he performs - based on those mechanics, and the DM's judgement - and on how the DM decides NPCs perceive him. Of all those factors, only the choices made by the player at chargen & level up are under his control, the rest is D&D - Dice-luck & DM-judgement.To which I said that's a ridiculous way of looking at it, because even if you have the "best" mechanics for your character, you are still going to have a whole heap of failures. So those "best" characters are not the requirement for being "competent"... how the character is perceived in the game world does it.
Even the best mechanical stats available don't readily deliver under BA, because consistency is a major marker for competence, and you're unlikely* to ever overwhelm the d20 that way.I really just should have said "competent". A "competent" character in the game world just needs to be seen as such by the people within the world and within the story. They do not ALSO need to have the best game mechanics vailable too (despite the claims of others).
Conversely, getting the DM to consistently narrate success for your character's area of competence will deliver...
...and I'm not sure that isn't the point your making?
* notable exception being the Rogue's reliable talent class feature, at 11th.