Hahaha that's what frontend devs think, but the backend requirements are just as vague: "Just make this button work". In my example all the requirements would actually be figured out bit by bit over months, nevermind the prescience required to foresee future architecture-breaking features or scaling requirements. At least you can make a mockup and get instant feedback, flawed as it is.

On either side it takes experienced engineers to suss out actual requirements from customers/PMs. The main difference is that the backend (especially on the infra/devops side) is only accountable to itself if everything goes well, but ironically that means no-one knows or cares about the amount of engineering that goes into keeping PMs blissfully ignorant of the risks and complexity.