There are plenty of conveniences in sports.
It's convenient that Richard Petty won his 200th race (his final win) at Daytona with the President in attendance, or Dale Jr. winning at Daytona in possibly the one and only time he'll drive the 3 car, his father's number.
It's convenient that Pittsburgh got one for the thumb at Super Bowl XL, being Jerome Bettis' last season, in Detroit, Bettis' home town.
It's convenient that the Red Sox were down 0-3 and down to nearly their last at bat against their arch rivals when David Ortiz swung and helped propel the Sox on a eight game winning streak, defeating their nemesis and going on to win the World Series and end their curse.
It's convenient that the two most storied franchises in the NBA, the Lakers and Celtics, retool and in a matter of a couple years, are playing against each other in the finals and winning championships again.
Are there circumstances where the fix is in? Of course. Do we know what, where, and when? No. Is every season of every sport fixed to draw the biggest revenue to their respective sport? Not only no, but hell no.