1. It's not.
2. It's older.
The B767-200 family is unlikely to secure any more orders (CO's order for 10 could have been the last) as the design dates from 1981, and hasn't received major upgrades in the form the 737 did with the Next Generation variants.
The B767-300 family is still selling albeit slowly although it has been on the line for over 15 years.
The B767-400 series is a niche aircraft built primarily to satisfy demand from CO
Finally, Boeing is switching attention to the 7E7 family, so asides from the anticipated military tanker orders, the 767 is in its final years of production. The generic type has sold in the region of 1,000, like the 757. Many which were retired post-9/11 by airlines like AA
are being snapped-up by carriers throughout Africa and Latin America, where they no doubt have many years ahead of them (regions where the A330 is doing not so well...).
The A330 is both younger and larger. The -300 is more a competitor to the B777-200 family (and replacement for the A300) while the -200 is the main (albeit late) competitor to the B767-300 (the A310 was Airbus's answer to the B767-200). For 10 years the B767-300 had little competition, remember. Comparative orders and deliveries for the rival types are as follows:
A310-200/300: 260 / 255 (since 1982)
B767-200: 248 / 242 (since 1982)
A330-200: 260 / 157 (since 1998)
B767-300/400: 697 / 678 (since 1988)
A330-300: 212 / 144 (since 1993)
B777-200: 498 / 424 (since 1995)
A330 TOTAL: 472 / 301 (since 1993)
B767 TOTAL: 945 / 920 (since 1982)
Given that the A330 is half the age of the B767, at this rate, it is quite possible that a similar number will have been produced by the time production closes. You may disagree with my comparisons, but they are the closest you can find between Airbus and Boeing and there is no obvious bias towards one manufacturer or the other.
[Edited 2004-07-20 02:56:15]