In my experience, when new ways of working (like agile) atrophy it is with a regression towards old ways of working not a descent into chaos.
We guard against the threat of chaos by applying sticking plaster fixes when issues occur rather than tackling root causes which often means changing mindsets and having hard conversations. These fixes often undo the foundations of the new ways of working we have implemented.
We expect the failure mode to be chaos but instead, we get more upfront planning & design, centralized decision-making, the disempowerment of teams, low-trust environments, vanity metrics, waterfalling work within sprints & between teams, etc. We cause the regression to the old ways of working.
At least in part, the antidote is to try to better remain true to the principles when addressing issues – but that’s tricky. It’s easy to go back to old tools.