I think Opus 4.7+ being annoying is actually indicative of something else: Anthropic is clearly all-in on building persistent end-to-end agents that act autonomously and direct agent swarms. As such, they feel less of a need to make the outputs pleasant to read for humans(especially at the cost of capability anywhere else) when humans aren't part of the intended operating environment.
I have never found a compelling reason to move past using Opus 4.6 for this type of workload so there is likely a lot of truth in your theory. The writing was on the wall that there was no reason for a new model unless that model could tackle a completely different problem space.