So, most of your speculation on future products is based on this unexplained uptick in performance of the Athlon 200GE, which potentially indicates that primitive discard is now working. What data are you basing the +30% performance gain of the Athlon 200GE on? I haven't been able to find anything that would indicate it has 30% higher performance than what we would expect vs the other Ryzen chips with Vega graphics.
As for the Navi as mainstream only rumor, I will agree that the rumors never made much sense to me. The rumors seemed to indicate that Navi would bring GTX 1080 performance in at $250. While all well and good, what does that mean for Vega? Vega would then be a more expensive high end GPU that performs on par with the new mainstream. So, without at least releasing a 7nm Vega refresh, that move doesn't make any logical sense.
Not to be a stickler, but I totally am. Didn't the RX 480 launch June 29th 2016? Or am I missing something here?
And finally, concerning the Polaris rumor.
Remember what AMD said: leapfrogging design teams so mainstream cards would release one year, high end the next, and alternate back and forth, which was the main reason for splitting off the high end series designations to their own brands (Fury, Vega). Also remember that Navi was ALWAYS intended to be a mainstream replacement for Polaris and to release in 2018, but also remember that Raja was massively behind schedule when he left the company. Lisa Su directly controls RTG, and has dedicated the vast majority of resources to the semi custom market, which effectively ties new graphics card releases to the semi custom market. Navi will power XBOX Scarlet and PS5, and with them slipping to a 2019 release date, AMD adjusted to enable a 7nm Vega for the professional market as it (quite likely) has an incredible performance advantage over 14nm Vega due to deep learning and other professional features which were slated to be included in 14nm Vega to compete against nVidia Tesla but did not make it in in time, while slipping Navi to 2019. "Polaris 30", if it indeed does exist, and it's not unreasonable to assume it won't considering TSMC's 7nm process is apparently quite mature already, will not be anything special compared to existing cards, as it is just a refinement of existing technology, nothing that will make or break playability, but will improve performance per watt as well as reduce manufacturing cost. Prices will still remain high due to the RAM shortage, AMD continuing to rely on valueless "free games" to sell graphics cards instead of price reductions (seriously, a $300 card with "free games valued at" $60 is still a $300 card), the high performance of the GTX 1060 and 1070, and the Mount Everest size pile of GPUs nVidia is sitting on due to overproduction during the cryptocurrency boom allowing nVidia to flood the market with cheaper GTX 1000 series GPUs.