You're arguing continuity; I'm arguing stability.
How many times did you quote me using the word continuity? How many times did you say stability? OK, whatever. People talk past each other instead of to each other all the time. It happens.
FWIW, I think "stability" is an imaginary problem. I don't think it's a thing that many fans specifically, particularly desire. All over the forums people talk about "excitement" of new members and new groups. Graduations/Departures have their own specific negative effects, but it's not "stability" that is lost.
So... yes... adding more young members now will reduce the left:staying ratio of the putative demographic crisis. But I don't think that's any kind of argument for using the word "need" much less "need Inoue."