googling pre-LLMs was a required skill. Prompting is not just for search if you build LLM pipelines. Cost commonly can be easily optimized 2x if you know what you are doing.
something being a skill does not mean it is an engineering discipline. engineering is the application of science or math to solve problems. writing prompts doesn't fit that definition.
I think a more fundamental aspect of engineering is that it involves well-defined processes with predictable results, and prompting doesn't check either box.