If we don't know what is or isn't in the actual DMG how can you make this statement, especially when every other edition has had required information, rules,etc. in the DMG?
Well obviously we can't know as it's not out yet. But we can know what's in the playtest documents and what they've said, and I am going off those. Have your read the playtest document and played the game to see whether you ever need the DM book portion of it? I have, and you don't. It's all advice and optional rules.
EDIT: In absence of concrete information we can only draw on past experiences... why should we assume they will be totally different than they have for the past 30+ years??
I found the 4e DMG to be almost completely absent of anything I needed to play the game, particularly once Essentials came out. Did you find it required?
Yes but why are we assuming all this when the history of D&D speaks against it?
Well first I don't think it does with 4e, and second because we have the playtest documents and what they've said and experience from playtesting it.
So I say again, assume you don't need the DMG to play 5e. If that is the case, and also assuming you can make NPCs using the PHB, are you OK with the $50 price?
It's like saying assume this one time water won't get your hand wet and has the exact same resistance as air when you dip your fingers in it... even though every other time it hasn't, assume that your hand can still pass through it like it normally does, now what's the difference between passing your hand through air or water... Why am I assuming this?
Yeah this isn't a law of physics, this is just a game. WOTC has gone from "Need the DMG for various things" with 3.0, to "need it less" with 3.5, to "Need it very little if at all" with 4e, to "Don't really need it at all" with Essentials, and it seems from the playtest and what they've said that it's now "You won't need it at all" to play 5e. I don't view this as some immutable law that never varies and it requires the Word of God to alter it.
So, assuming you don't need it, are you now OK with the price?