Hey Q,
That quote, to me, doesn't speak to the Mothers, or the change for Mother summer at all. It suggests that Mab (current) and Titania (current) became the Queens that are at the same time, or close to it.
That is all I was saying. As far as I recall I have never seen a version of the theory that involved the Mother's Dying until you mentioned it here, and I generally take the other WOJ to mean it would be nearly impossible to pull off anyway. All I am pointing to is that there is an apparent generational gap in there, because there have to have been more Queens (as in the middle mantle, specifically) than we have accounted for. The Currnent Mother Summer is at least one generation younger than the Current/Original Mother Winter. Which means that the current Mother Summer (we'll call her Betty, for Betty White casting), was once (within the lifetime of the current court framework)the Summer Queen while Mother Winter (Lets just call her Grouchy) was in office with the original Mother Summer, and with a Winter Queen serving under her, ie. Betty's queenly counterpart. That counter part is not Mab. Also, there needs to have been another Summer Queen to serve between Betty and Titania, to have died back around Hastings. So the pattern would imply there were more queens/generations in there, and with the exceptions in Harry;s lifetime, all the ones we knwo of have been actual blood relatives, so the family tree is either severely warped or there are more changes of mantles than we have accounted for so far. That was my only point.
I should have pointed out that the theory generally assumes that the generations and courts track each other, that circumstance if not any actual force of Balance has played out such that the Queens (and to a lesser extent ladies) are contemporaries of each other. If Winter had just one extra instance of Queenly turnover than Summer, to counter the shift that happened when the original Mother Summer retired, it all fits fine.