I agree that now what's good or bat will be a comparison with your peers.
2x might be awesome if your peers are 1x. It might be bad if they are 4x. We'll be optimising local maxima. Per company.
The multiplier won't be such a precise number, but rather more of a feeling of "X person seems to be producing double what I'm producing". It will definitively be used as criteria for employment for a while.
Then the industry will converge into a "new normal". Best practices will propagate fast thru the industry, and all developers will have a similar baseline. Dev that were great before and doing 2x, will continue to do so. Same for underperformers. The industry as a whole will produce a whole lot.
IMHO, this will only raise the bar. It will define what's the new normal.
Pretty fair - I think anyone who has developed the sensation of becoming their own bottleneck understands this. And yes, if you can simply be twice as productive as you were prior to LLMs, then that is an improvement. What I worry about is that that multiplier will become a criteria for staying employed. I.e. if you were a 1x developer, and now you're a 2x, why would a company keep you in position knowing they could instead hire someone who's 5x, 10x, 100x, etc. They might feel like they are losing out. This is all relative.