I see your point, this also likely made it way overused, which in turn hurt variability of vehicles in matches.
I am not saying that I know, how Gaijin balances the game, but from info I have, could see that for them T26E5 was clear outlier that visibly sticked out in statistics (likely win rate and pick rate at least).
Given that in Sim we are limited to just 3 vehicles, pick rate might be more important metric than in other game modes.
(my speculation) Also this bracket seems to be limited to lower part of 6.7 RB spectrum, which T26E5 is obviously not, so I could see it being more fitting to higher brackets in this regard as well.
If you look at the bottom of the post you linked you can see that a manager posted 2 months ago that a solution is in the works. Hope it comes in December.
