But the issue isn't coding, it's doing the right thing. I don't see anywhere in your plan some way of staying aligned to core business strategy, forethought, etc.
The number of devs will reduce but there will still be large activities that can't be farmed out without an overall strategy
Why do you think this is a problem? Reasoning is constantly improving, it has ample access to humans to gather more business context, it has access to the same industry data and other signals that humans do, and it can get any data necessary. It has Zoom meeting notes, I mean why do people think there's somehow a fundamental limit beyond coding?
The other thing you're missing here is generalizability. Better coding performance (which is verifiable and not limited by human data quality) generalizes performance on other benchmarks. This is a long known phenomenon.