As someone ho fits this description, I think I can offer some insight on this. The reason it looks like online heroes are live zeroes is that the information regarding live players is young and incomplete.
Online players are called online players for a reason. They play mostly online. Take me for example. I played like 10 huge field tournaments this year at the
wsop and that was the extent of my live results for the year that were published. They don't publish how I did in cash games, which I happened to destroy while I was there.
So if I play 10 large field events a year, even a great tourney player only expects to cash around 16% of the time. A great tourney player makes a final table in about 4% of the events he enters when field sizes are about 1,000. The ones I played were 2,000 on average, so a great player makes the final table about 2% of the time with 2,000 people. So the fact that some online guys haven't seen a final table when most have played under 25 tourneys lifetime, doesn't mean much.
Another thing to think about is that live players don't usually have much success online either. And usually the same argument holds true. Live players may play 100 tourneys in a year online, and it is not uncommon at all that they don't see final tables very often or because online is harder, their cash game play usually doesn't work well for online games and by the time they might try to work hard to adjust, they move on to their real game which is live poker.
I think the main thing to realize is that cash game results played in a casino are almost never reported. And that is where most online players do so well anyway. I have had great success in live games over the years, but with limited tourney experience live, I just don't have the volume to really have a sample size worth discussing. If I play 1,000 tourneys in my lifetime and have few cashes and no final tables, then I think it will be safe to say I am a live "zero" but until then, I don't think there is much to discuss.