Because "platform engineering" isn't about writing bash scripts, it's about having a mental model of the system architecture. (Which the LLM definitely doesn't have.)
Also, it's always the case where you think LLMs are great at doing whatever it is that you don't understand or value.
There was lot of lofty ideas around devops/pe and the like but ime the grim reality is that in most of managers’ heads it’s basically “tools that product engs don’t want to be concerned with” and like i said current models are really really good at this. Also disagree on the mental model thing - give opus 4.7 or latest codex access to your code, design mds and your logging mcp - in five minutes it will be better at debugging production issues than 90% of platform engineers I’ve worked with. It is truly over