Oh that's lovely. Just what we need: parts being exclusive to OEMs like Alienware.
For "enthusiast" performance parts, I really doubt that AMD would do that. If they do, they're stupid. One of the biggest pieces of Ryzen's success story, has been the enthusiast DIY crowd, and AMD's support of such ("all AM4 CPUs will be unlocked"), and not some big OEM business deskop buyers. (No iGPU in the "bigger" Ryzen CPUs is one good reason.)
It would be a real "kick in the teeth", if those really high performance parts were OEM-only. Can you imagine if ThreadRipper were only available from boutique OEMs, and not directly DIY retail? Then again, I don't know AMD's "return rates", for those higher-end CPUs. Maybe many a n00b builder attempted to build a rig around a $699 CPU, couldn't get it working, and returned everything, and AMD had to eat the cost (even partially) of the expensive TR4 CPU?
Maybe the VRM and cooling requirements are such that the 3950X should only be attempted to be system-integrated by "experts"? Granted, we do have plenty of those on this forum, myself hopefully-included. (Though I have yet to build a custom water loop system. Y'all that have, are ahead of me still.)