The potential also comes as a 'cost', not to mention that most sites already test Ryzen with DDR4-3200 already.
I've said this many times before, and your post illustrates it perfectly - Ryzen *needs* faster memory to be competitive in gaming. And by competitive I mean to be considered a worthy alternative to Intel, because even with DDR4-3200, Ryzen is still slower than an i5 8400,
even if the 8400 is running cheaper DDR4-2666 memory
https://www.gamersnexus.net/hwreviews/3086-intel-i5-8400-cpu-review-2666mhz-vs-3200mhz-gaming/page-4
I think this fact gets missed a lot when people do value comparisons. Whilst it is often mentioned that there are no cheaper alternatives to Z370 mobos for the i5 8400 (a valid point, may I add, especially for a locked CPU) how many people asking for honourable mentions for the 1600/1600X based on price mentioned that you need (as of today) really expensive DDR4-3200 CL14 RAM just so it can be in the same rough ballpark as a stock 8400?
Of course, you can also run DDR4-2666 with the Ryzen setup and save $50, but is it worth the peformance penalty? Probably not. Actually, I would like to see this tested - Ryzen 1600/X vs i5 8400 running more budget friendly DDR4-2666. I suspect many AMD fans wouldn't want this scenario tested though, because AMD would lose additional ground in gaming, and they are already behind to begin with.
Matter of fact is, neither CPUs are in truly ideal situations for budget builds: the Ryzen chips need fast (and expensive) memory and the i5 8400 needs a more expensive motherboard because there are no other choices right now. The cheaper mobos for the i5 8400 are coming, but will RAM prices come down anytime soon?