The value of good editorial staff may very well be less important in some fields. In the biomedical field subject-matter expertise still matters a lot in terms

The value of good editorial staff may very well be less important in some fields. In the biomedical field subject-matter expertise still matters a lot in terms of discerning good research from seemingly good research. Which also means that prestige journals won't make research any more groundbreaking but if functioning properly should enrich for papers that are less likely to be junk science. I'd also argue that generic journals like Nature and Science are so unfocused that their staff probably provides little to no additional expertise and they rely entirely on peer review. Whereas staff at more specialized journals with lower but still very respectable impact factors are probably doing more informed work to select for quality science.