Ovinomancer
No flips for you!
Ok, I'll bite:
The Strongest Man in the World became too proud and (insert some god) struck him down with debilitating joint pain. He can barely lift a mug of beer without experiencing crippling agony. So he doesn't.
The Strongest Man in the World accidentally killed (insert somebody he loved). He swore an oath to never use his great strength again.
That's all I got off-hand. Admittedly it's tougher to do this for attributes that have outwardly obvious, physical manifestations.
But, regardless, what's wrong with those character concepts? While they could be played farcically, I don't think they are inherently so. As long as you trust your player to not suddenly say, "Ok, I guess I'll use my great strength" it's functionally equivalent to having 5 Strength. (If I recall correctly, one of Max's objections was exactly this. I.e., that players couldn't be trusted not to try to exploit the fluff as mechanics.)
They're backstory, maybe, but not a coherent character concept. Neither of these can ever choose to overcome or ignore their built in faults and will always operate as weaklings. When you're functionally a weakling, the claim to be the strongest man alive is farcical and incoherent. You can do it, sure, but it's not in the same ballpark as a scrappy urchin background urban barbarian. That concept refluffs around the mechanics -- it doesn't attempt to narrate against them but instead with them to provide a different story that still supports the mechanics. The 5 STR strongest man is an exercise in narrating against the mechanics, as is the 5 INT "genius." The story you're telling isn't of the strongest man or a genius, but of a magically or emotionally hobbled person that isn't whatever you're claiming them to be anymore, but is instead something different.
Regardless, we hashed this in the other thread -- no need to relitigate. My point is that you can be on your side for this topic, but not agree that 5 INT geniuses are the same thing as this topic. More "staking out a middle position" and pointing out why rather than challenging you to reopen the 5 INT thread.