Yes!

But imagine if the developers themselves could break down the external requirements into engineering needs!

Or are developers grug brains that need a bigger, superior brain to simplify scary real world into simple, safe engineering needs? Or developer grug so busy, must write code, no time look at feedback form, no time think client request, need simplified instructions, must slap keyboard, clack, clack?

Context: https://grugbrain.dev/

Breaking down requirements and being the domain expert are not the same role. Engineers can break down requirements perfectly well given they have context of the code and systems and possibilities. A even bigger advantage is that there are multiple developers on team which means they can review each other's work. Just like a lone dev tends to go off the rails eventually so does a lone PM and almost all PMs are lone if they're the sole domain expert.