Oh well, it still proves my point, that older stories can easily be rewritten to comform easier with the current status quo.
I thought your point was characters should age, that means NOT rewriting stories, specifically origin stories, as they set a specific date from which to age from.
If a comic doesn't want a long-established character to age, their origin stories should be reworked so that they start off a lot closer to the present. Or, in the case of characters such as Dum-Dum Dugan, who have close ties to WW2, they should already have recieved their anti-ageing treatments a long time before the "beginning" of the age of heroes, not after the point where the sliding timeline started, because the date would end up being so long after their birth that they'd already be dead. Alternatively, they could have characters ageing normally, but I guess that won't be happening any time soon....