No it doesn't.
The upper body progression is just as fast if not faster than giving a complete beginner a shitty split routine.
The biggest difference is that the lower body progression is fucking light years ahead of the lower body progression on said shitty split and this makes people like you think that the upper body progress is bad because you are comparing it directly to the lower body progress.
Faster lower body progress is completely normal. Humans have most of their strength in their lower body by nature. The lower back and legs are the strongest muscles in the human body and if your bench is within 90% of your squat, you are horribly imbalanced.
SS will give a true balance of strength while most brosplits turn you into a top heavy retard.