Now, an "effective engineer" can be a less battle-tested software developer, but they must be good at system design.
(And by system design, I don't just mean architecture diagrams: it's a personal culture of constantly questioning and innovating around "let's think critically to see what might go wrong when all these assumptions collide, and if one of them ends up being incorrect." Because AI will only suggest those things for cut-and-dry situations where a bug is apparent from a few files' context, and no ambitious idea is fully that cut-and-dry.)
The set of effective engineers is thus shifting - and it's not at all a valid assumption that every formerly good developer will see their productivity skyrocket.
I don't think that it lowers the bar there, if anything the bar is far harsher.
If I'm doing normal coding I make X choices per time period, with Y impacts.
With AI X will go up and the Y / X ratio may ALSO go up, so making more decisions of higher leverage!