My working hypothesis is that people who are fast at scanning lots of text (or code for that matter) have a serious advantage. Being able to dismiss unhelpful suggestions quickly and then iterating to get to helpful assistance is key.
Being fast at scanning code correlates with seniority, but there are also senior developers who can write at a solid pace, but prefer to take their time to read and understand code thoroughly. I wouldn't assume that this kind of developer gains little profit from typical AI coding assistance. There are also juniors who can quickly read text, and possibly these have an advantage.
A similar effect has been around with being able to quickly "Google" something. I wouldn't be surprised if this is the same trait at work.
That said, if the language has GC and other helpers, it makes it easier to scan.
Code and architecture review is an important part of my role and I catch issues that others miss because I spend more time. I did use AI for review (GPT 4.1), but only as an addition, since not reliable enough.