This is true. When I started the Grey Wizard, I had already experienced the A-bomb twice. I figured I had at least 150 to 200 hours of non-MQ gameplay (which is still quite a lot) before he'd have to hunker down and finally start the MQ.
I've never been hit by the A-bomb (although I suspect that Fortja, at something over 300 hours, was close to it.) I never play a single character to high enough hours to worry about it.
I've only done the MQ at fairly low levels, simply because the characters who would do it at all are the ones who would take it seriously. "The Emperor needs me; I can't let him down!" Kara Whey just finished it at Level 11. I think Fortja was level 2, although she may have turned 3 before the conclusion.
I have the advantage of mods, though. Kara Whey has stashed away more than a dozen nice sigil stones, and she has the benefit of the Quest Award Leveler, which will max them out if she waits to level 17 to use them.
I often wonder, when people wait until high level before doing anything, to maximize the rewards: What are they doing until they get to that high level?
I'd rather play, I guess.