I posed that very same question the other day and noone seemed to know, but by chance I actually found that out tonight, after a concert where the soloist was a young cellist who I'm friends with since music academy and now plays here in a major Lisbon (Portugal) orchestra. This is mostly hear-say, but the sources seem very reliable.
The story goes like this: Last year the principal bassist from that orchestra reached the age of 65, which by Portuguese law requires people to retire from their employment. He was willing to continue, he's a monster player, but the orchestra decided to abide the law exclusively... too bad for them! It seems the man decided he wasn't going to just keep himself the rest of the time at home with nothing better to do (although if it was me, I would found a lot of fun things to do!! but anyway...), although he's still theaching, and decided to apply for the brand new, top-of-the-line, obscenely wealthy, National Symphony Orchestra of Qatar.
And at the age of 65(!) he's becoming their principal bassist!!

Oh, as for Mr Sheata... he apparentely left the Berlin Phil to join this same orchestra! And he's going to be that old man's stand partner... the inside player!
Never judge a book by his cover... or it's age! It might still teach us a thing or two!

Wow!