Don't blame the professionals, they probably could do that, too. At least most of the time. Blame their managers who don't know a fuck about programming yet think they know better what to do and how to do it best. Of course the programmers have to follow those guidelines, even when they know they're misleaded.
Well, the managers are 'professionals' too, technically... :P
I would say they should've just given the whole trilogy to Panic Button, but they're already so ridiculously overworked (Doom 3 is their 3rd Switch port this year alone) I worry it would affect their work on Doom Eternal.