I think PHANTOM can definitely reach 10,000 performances
To think, the show has never even done stunt-casting before. If they ever even had to reach that point where they had to, I'm sure they'd be able to find celebs pretty easily that'd want to do (the question would be if they could do it well...), but thats beside the point.
But yeah, I think PHANTOM will keep running, even if they started having lower attendance/ticket sales, the producers still have loads of money to keep it going.
My 2007/2008 Season:
Grey Gardens (7/5)
110 in the Shade (7/6)
Mary Poppins (7/7)
Xanadu (7/7)
Deuce (7/8)
Spamalot (7/8)
Jersey Boys (8/25)
The Year of Magical Thinking (8/25)
Mauritius (11/2)
Young Frankenstein (11/3)
Rock 'N' Roll (11/3)
Pygmalion (11/4)
Mauritius (11/10)
Mauritius (11/21) Mauritius (11/21)
Sunday in the Park with George (3/6)
South Pacific (3/7)
Gypsy (3/8)
Cat on a Hot Tin Roof (3/9)