Fanaelialae
Legend
In fairness, I'm pretty sure the DMG does address that point. I believe it says somewhere that if you have martials, they need a magic weapon. So it's more like "you don't need magic items, except for a magic weapon for each martial character". Which is basically true. But what they don't mention is that running a low magic item campaign gives casters a much more dramatic advantage over martials.5E:"You don't need magic items."
MM: Half the creatures are resistant to nonmagical attacks.
Which is why one of the fighter fixes I've proposed (in other threads) would be to let them pick a magic item as a class feature. But it's gotten a lot of pushback in the past. I guess because it's a form of narrative control (albeit, in the most minimal sense possible).