I mostly agree with you, but
HeisenbergFX4
have a point. The Series S is somehow able to be considered a next gen console even if in raw TF (and RAM) it is somewhat inferior to the Xbox One X. But having a more modern GPU and the new CPU more than make up for it. It would be the same for the next Xbox. Even if in paper it will not be the 8x increase that we got this gen, it will not be limited by 2020 AMD tech, and will be a lot more future proof as a result. If we were not talking about Xbox, but about a good competitor, being 2 years early would mean having 10 to 30 millions consoles by the time the PS6 is there. Enough to be relevant and force third parties hands. The series S make IMHO talking about the next gen Xbox a fascinating subject because with such a disparity it make cross games weird to imagine. If PS5 games go to 720p reconstructed to 1080, what will happen to Series S games? 480? Even less?
I agree with you that it will be a bad idea because I think that third parties will simply consider it like a Pro version regardless of what Microsoft will say: a game that can be played on the Series S will not be using this next gen console well, and Xbox will not break the bank for exclusivities as they want for all games to be on Gamepass for at least a few years. It will be interesting to see how the market will react in a few years.
My problem with this 2 years windows is that with Gamepass they will assurely do as this gen and make all of their games cross gen. So it will be seen as a late answer to the Pro by the industry unless it somehow get marketed so well that it sell more than a PS5 that will naturally be a lot cheaper by then to make life hard for Xbox. I can't see the benefits outweight the loss and I think that unless they either really have a good grasp of the US market and/or are ready to do it like the PS3 and sell for half the cost of making it I can't see this work well.
As for the Series X refresh, I am not sure that it has been cancelled. No insider so just a feeling, but Xbox really like to compete on price and did so a lot in all Xbox generations. I can see them trying to make those consoles as cheap as possible and wait for next gen. A series X at 300 and a Series S at 200 or less would really sell if the games are there and it should happen one day I think.