I believe on the official D&D, they admitting that the 5.0 DMG was rushed and fully designed last of the core 3.
I fully believe that due to lack of time and the fact that the goal of 5.0e was to draw back in old fans, it was haphazardly stuffed with stuff they thought a 1e DM, 2e DM, 3e DM, or 4e DM would want. New DMs were and afterthought due to the belief there wouldn't be many that having played under an old DM in the first place.
And they happen to be right. Many of the famous D&D 5.0 new DM influencers and celebs admit to not even seriously cracking open the book.