How do you not realize that you're contradicting yourself? :
If it actually was a good build path, then you'd see widespread abuse
she was probably also bad back in the day
You yourself realize AND admit she was a bad pick. Yet at the same time you talk about "abusing" a successful strategy. Since she was a bad pick, it's impossible for players to "abuse" anything with her. She's simply not picked. The trolls in your bronze games that picked Quinn did so because they liked her despite being bad. They didn't care what her most successful strategy was, they didn't even care to learn what class of champion she's supposed to be. As the mindless sheeple of bronze that they are, they believe the lies Rito tells them and unintentionally troll because Rito wanted them to troll.
I will admit one thing, you're right about the "small" subset in high elo. Roughtly **ONLY **95% of Quinn players took bruiser builds on her. Interestingly enough, that 95% directly correlates to the exact same 95% of Diamond players that picked her top lane. A MASSIVE FIVE WHOLE PERCENT OF HER DIAMOND PLAYERBASE built her somewhat more "assassiny," namely the 5% of games where she was played mid lane. In roughly 100% of Quinn games, her very first item was BoRK and (excluding Trinity Force, which still gave crit back then) somewhere around 0% of Diamond Quinn players bought Crit on her.
These are facts.