I don't think so because the overlapping generation explanation buys them 30 years since Mark Sanderson is part of the second group that overlaps the first group and he is only 50...he lives to 80 and that means the Big A could still be 30 years away and the GB prove themselves correct.
So I think the current explanation is perfect in the minds of the GB as it makes it sound like it is very soon whilst in fact it could be 30 years away...I think the GB want that explanation so they can forget about the "generation" explanation and move onto other areas like 1914, 1440,000 etc.