This is gonna be a bit long.
Well, we must see that williams is already 70 years and more...and a man´s life expectancy is of about 75 years. We must see also that generally, musicians lives much much more than common people...I don´t know the reason for this, but it is true. Soemone said that Zimmer Could replace Williams, but I say: Nobody shall be able to make the music that williams creates...nobody. I think that if this happens, Lucas should look for an re-edition of the already created music, and for an Musician who makes some versions to original themes.
And, I´ve wondering why williams hasn´t won the oscar academy Award recently...I know that you, american people, love the exotic things, and that might be The reason why Goldenthall won the Oscar this year, but, believe me, as an Latin person: Frida´s score is not original at all; it sounds almost like an "Ranchera" Cd, and, it is not worth enough to recieve an award like Oscar.
Star wars music was really much much better, so as Harry Potter.
Finally, I want to say: Williams has done a thousand times what any other musician could during his life; nobody, Shore, Zimmer, Horner or anyone will be able to get his genius.