I doubt stat at 6 will completely eliminate chance of success. That woud be stat at 0, which cant be done. Sucess is calculated by formulas and only 0*something give a zero.
Chance can however be extremely low, thats true, and very likely. Stat at 6 will definitely mean you are very bad at that thing.
Gear will possibly add some stats. So people can go 10 dex, 14 str, and then add more str with gear. Or they can go 6 dex, 18 str, add more dex with gear and achieve same result.
The question is how you wanna walk around naked, after you have been killed and looted.
Perhaps if dex is giving movement speed, you want higher natural dex to get into game faster after you have been looted and are naked so 6 dex and then increasing it with gear might not be the best choice, because you will be very slow while naked, and getting back into game will take longer time. And this is pvp game where you will die and get looted a lot.
Havent yet seen people theorycraft from this aspect. All I've seen is people theorycraft for ideal situations.