There's always the possibility that years from 
now, anime will be seen as an art style, sort of 
like Gothic ivory sculptures or the Ancient Greek 
style -- where pieces might have no obvious 
authourship, but have meaning because of their 
association with their period. Anime cels are 
beautiful and they have a definite style. 

(Anyway for the popular old masters, they often 
had assistants who'd paint background and 
sometimes the entire painting in the chief 
artist's style. There are letters where customers 
would write to the artists, that they must at 
least paint the faces of the figures.) 

(Please don't see this as an attack -- just as an 
opinion. As someone once told me, for every 
argument there is an equal and opposite point. 
Only time will prove you or me wrong. :)

Hmm -- popular series do have more of a chance of 
survival. Books by Dickens, the Brontes, Austen, 
and Thackery were best sellers in their time. 
Shakespere was a popular playwright. On other 
hand, being popular does not necessarily succeed. 
Afterall, ever read Charlotte Young recently or 
Graveyard poetry? 

(Someone made an argument, that things survive if 
they attach to something larger than current 
fades. Love, revenge, basically the things that 
don't change. Charlotte Young was into the 
brother-sister-creepy relationship thing that was 
popular during the time.) 

Tenchi does reach out to other people, and a lot 
of people use it as an entry piece for the anime 
genre -- not to mention influenced the designs 
for the studio for other series, and it might be 
seen as a pioneer, so I think it might survive. I 
think the magical girlfriend genre will always 
have an appeal. ;)   
Bubble Gum Crisis and the Lodoss War has been 
around since the early 80's, and they don't show 
any signs of abaiting. 

Who really knows?