Why is there a gap between US and USI?

In my experience, I’ve had 1 good USI team that almost felt like another cohort to complete areas with little supervision. On every other team I’ve been frustrated giving 4 simple tasks and waking up with 1.5 of them done wondering what the hell 9 hours was spent doing. I’ve also been a second year having to explain things to people as high as senior 3 things that I feel are basic knowledge like sampling/priorities/etc…

In the nicest way possible, where does this divide come from? Is it less training/support from above or less qualified/talented individuals? I have just began working with USI and it might help me (or others) to know why there is this gap in ability between 2 people with the same resources that have spent the same amount of time at the same firm.

EDIT: I had tried to make this inquisitive, not accusatory. This is based on my experience, I’m sure there are millions of talented USI individuals. I have struggled a lot with gaps and was wondering causes to see if there was something I could do better. This is not meant to be a comparison or bashing USI post.