Similar to the Pirates etc in baseball. Incentives matter and both the Bills and Pirates have lost for a very long time and claimed it was for "small-market" reasons. Some of it may be, but it can also be because it is more profitable (at least from a risk and return perspective. (Winning big costs money and comes with a greater risk.)
From Gregg Easterbrook (Tuesday Morning Quarterback is BY far my favorite football read)
"Each NFL team gets exactly the same national TV payment whether it's winning big on "Monday Night Football" or losing badly and never aired nationally. Ticket sales can vary and generally are where the profit resides. But the revenue swing between packing the house and having a poor gate just isn't that great.
Most teams go into the season knowing they will sell about 90 percent of their seats no matter how they perform; a few know every seat will sell regardless of performance. In 2010, even given a slack economy, the league average was 94 percent of seats sold, and every team except Oakland and City of Tampa sold at least 80 percent of its home seats. Winning can help sell tickets, but even a clunker season will fill most of the house."