Agreed - I am generally very wary of issues regarding author rights, but the DM's Guild Agreement is a rare case of contract law that is so bad it is good, maybe even for folks without recognized names in the industry.They would be doing work for hire and it would all belong to WotC either way. This way, they can publish without editor or developer feedback, meaning it can be more of their own voice and artistic choices.
You're going to make peanuts off of anything you create, and none of it belongs to you, but you gain access to a huge amount of D&D lore for use as a construction kit. The only other way to get that access is to be hired as a freelancer for Wizards, and that's a pretty narrow bottleneck that results in you not making the product you want or retaining ownership anyway.
For me, at least, that's the real dragon's hoard -- I could care less about the SRD 5.1, give me that setting material. Someone's got to iterate on it constructively while Wizards is focused on nostalgia cash-ins, and being a part of that has value on its own.