This seems like it was developed with the new player/DM in mind.
It's definitely WotC's strategy, they've mentioned recently that beginners/newcomers are considered to be a much larger share of their customer base than long-timers.
In fact personally, I don't think I'll ever need another DMG, and I didn't really need the 2014 DMG either if it wasn't for the magic items. While it certainly doesn't hurt to refresh your mind by reading another DMG every now and then (and not just for D&D), I think most of us would buy it only for fear of missing out, as in "it's a new edition/revision, I
have to buy at least the core books".
It looks like they have done a great job in re-arranging the DMG, making things easier to find and use as well as putting a lot of cool stuff in one place and some that wasn't in the 2014 DMG.
I didn't like the order of the 2014 DMG, it gives too much of a top-down image of what DMing is about, because it starts with worldbuilding, then adventure design, and then running the game.
It shouldn't be difficult to realize that ALL DMs need to learn to run the game, but only SOME DMs also want to design adventures and settings. Going bottom-up could make it easier both for beginners and gamers coming from another edition, to immediately jump into the game, just try out a sample adventure to learn how the new ruleset work. Heck, I'd even put a sidebar at the end of the first chapter saying "close the DMG and run your first game, before reading the rest!".
I think there's a difference in the fact a lot of these creators have made videos, and profits, saying 'WotC failed to address this, and so here's what I eventually had to do' to then, some years later, say 'Wow, it was there the entire time'
Video creators only really create entertainment, and ranting or raving are the two most effective techniques for that, they rarely create usefulness.
Something I appreciated about the 3.5e DMG was all the "behind the curtain" sidebars - where the designers talked about things like the possible implications of implementing rules variants and such. I wish there was more transparency like that in the 5e books.
I loved those sidebars! The 3.0 DMG was my first DMG, and it taught me enough to start as a DM rather than as a player with the 3e edition (even though I had played already BECMI before, so I wasn't completely clueless of D&D). The 'behind the curtains' sidebars made that book really feel like it wanted the reader to be part of the game design process itself.
Yes, downtime is a substantial portion of our game - pretty much anything that isn't an adventure. We can easily spend a whole session or more on "downtime"
There's a difference though, between "incorporating downtime" and "incorporating downtime
rules" in a game.
Lot's of gaming elements exist, that for different groups can be important, unimportant or even detrimental. Being important though doesn't imply hardcoded rules are used. For instance,
exploration is my favourite pillar of the game, but
exploration rules often get in the way for me.
WotC's problem is which elements to feature within the DMG, and for which of them to provide hardcoded rules vs sensible guidelines only. I guess they have some statistics to rely on, because personally I can't figure out what usefulness is there for me from stronghold building rules and siege engines for example... Downtime is something we dedicate a significant attention to, but hardly use any rule for it.