Baseball----- at the turn of the 20th century there were two separate leagues, the National League and the American League, and to determine a champion, the two best W-L “round robin” winners from each would face each other in a best of 9 (then reduced to 7) “World Series”. This expanded into “East” v "West " playoffs in the 60s because more teams were added and it became too difficult because of the amount of teams and travel for both leagues to determine WS participants based on a simple round robin system.
This was expanded to East-Coast-West champions + wild card in playoffs from each league in the 90s when the league went to three divisions per league because of further expansion and TV scheduling.
The recent second wild card team is an artificial creation to create fan interest and include more teams in the “playoff race” and thus more fan interest as the season winds down.
NFL—of all the American sports, football lends itself best to playoffs because of the short 16 game schedule; by all rights MORE teams should be allowed, not less, to determine a true champion. The NFL, when it used to be only 12 games, used to put East champion v West champion in a single NFL championship game. As the league expanded, playoffs were added, and then finally a “Super Bowl” with the AFL champion. Playoffs have since expanded further, but with 32 teams, only 16 games, you can see how a “round robin” format with all 32 teams playing each other on an annual basis is a mathematical impossibility.
Many American sports fans gripe with the 16 team NHL and NBA playoffs because of their already 82/80 games seasons. The NBA at least makes SOME sense: because of geography, it was impossible to have teams stretched over the country to play each other a set amount of times; that said there have always been inter-division playoffs which resulted in the NBA Finals going back to the 50s. Basketball is a sport that seems to love tournaments here.
Of all four leagues, the NHL has always been the biggest culprit when coming up with illogical and unfair playoff systems. There was one point when the 1st and second best regular season teams would play each other in the FIRST ROUND of the playoffs. In the “Original Six” era even though there were only 6 teams, all within a reasonable travel distance from one another, even after playing 70 games where surely, a Champion could be determined via round robin Won-Loss record, the top 4 teams would still enter a Stanley Cup Playoff.
In 1966-67, when the league expanded to 6 teams, the Original Six would be placed in the Eastern Division, and the survivor of the same 4 team playoff would face the winner of the four team playoff—from the Western Division—consisting off all brand new Expansion teams! (IIRC, the St. Louis Blues would get blanked, 4 games to none, by Montreal the first two years).
In the early 80s, despite only having I think 21 teams in four divisions, the NHL, now after a 82 games season, would allow the top 4 teams from each division in the playoffs-----with each team trying to playoff out of its own division, then conference. In other words, you would play 82 regular games to eliminate 5 of 21 teams from the playoffs, bringing up decades of complaints about the regular season being meaningless.
Im not sure what the NHL’s fetish is with playoffs, not that they aren’t great, but I’m guessing the roots might be somewhere in the Stanley Cup Charter; and a desire to milk an extra buck out of the fans and TV networks.