It doesn’t always happen but it’s certainly a surer bet than any given baseball game. It also takes a ton of time to recover between games, so a series wouldn’t be feasible. You have the occasional upset, but very few Cinderella stories in CFB or the NFL. Patriots over Rams in the early 2000s and Giants over Patriots are the biggest upsets I can think of.
March Madness is awesome, but it’s very different given the number of teams and nature of the tournament. If the NBA Playoffs were one game series it would be terrible.