That’s one misconception about leaving cloud people think it’s a one time cost compared to opex, but in reality you are just moving the spending. Devops for your now custom on prem workflows, toil due to inferior tooling compared to cloud, physical costs like electricity and cooling, space for the racks, physical security, high availability, etc I mean there’s so much downside.

I said "doesn't necessarily rule it out" rather than a stronger claim advisedly.

You're entirely correct that there are an unfortunate number of people who hold that misconception, but (a) I'm not one of them (b) that wasn't my point.