There’s been plenty of very good and great Guineas winners beaten at Epsom, though on reflection, it probably wasn’t the greatest Derby. Treasure Beach ran ok a few times afterwards, but Carlton House clearly wasn’t top class, Memphis Tennessee likewise or Native Khan. Who knows what Pour Moi would’ve achieved, but they finished in a heap that day, so chances are he was of a similar level.
The getting to settle problem would be been the biggest issue as others have said, there’s no way he’d have won had Queally let him go like he did at Newmarket and chances are, Epsom would’ve set him alight with the crowd and all the distractions. I think they wisely swerved it, though I’ve never understood those he doubted he’d stay. Surely a horse who won twice over a mile at two, related to probably (certainly not confirmed) stayers like Noble Mission and Bullet Train by Galileo, would’ve got the trip, if not at that stage, certainly to have run well in an Arc?