When they sold them side by side, the 757 was twice the price. Few airlines ever used the jet to its fullest. Most were used on 2-6 hour flights. A 900 Guppy does most of those flights for half the purchase price, and 20% less gas.
Airbus got the market covered better. The 321 is better than a 900.

The 757 is still my favorite airline. A new 321 might be second. In theory they should fly the same as a 320, but i liked it a lot more.