Off topic, but why does the season end so much later?
And now, Selma's history of baseball.
In 1956, teams only played 154 games. There were only 16 teams. And they didn't fly or RARELY flew. The furthest team west was St Louis. It was quite common for Thursday to be a complete off day (no games whatsoever) because of travel. Basically, the season began around April 17th (seriously - that was the first day of the 1956 baseball season). The 2016 season began on April 3rd (and the 1996 season twenty years ago began on March 31).
In 1958, the Dodgers and Giants both moved from New York to the West Coast. They wanted two teams so as to make road trips to the Coast economical (it was originally supposed to be the Washington Senators who moved to LA...so in 1961, the Senators moved to Minnesota and became the Twins. Baseball also added two teams to the American League - the Los Angeles Angels (more name changes than John Cougar Mellencamp) and the 'new' Washington Senators (now the Texas Rangers). They also ADDED EIGHT GAMES to the regular season schedule.
In 1962, the NL added the Houston Colt 45s (now the Astros) and the New York Mets to replace the Dodgers AND Giants.
So in 1962, there were TEN TEAMS in each league.
There were no playoffs. The teams that finished first in the two leagues met in the World Series - period.
In 1969, baseball added four teams: the Royals (replacing the KC Athletics, who moved to Oakland in 1967), Padres, Montreal Expos, and Seattle Pilots. When they now had 24 teams, they went to six teams in four divisions. This was GREAT - because now you had FOUR pennant races instead of two. So they added the round of playoffs that from 1969-1984 was 'best three of five.'
After 1969, the Seattle Pilots went belly up and a week before the 1970 season began, they moved to Milwaukee, replacing the Braves (who had moved to Atlanta in 1966) and owned by future commissioner (and used car dealer - seriously) Bud Selig.
In 1977, baseball added the Toronto Blue Jays and Seattle Mariners (replacing the Pilots after six solid years of lawsuits) to the American League. This meant we had 26 teams with 14 in the AL and 12 in the NL.
In 1985, the LCS was changed to best of seven.
Can you kind of see now why the season ends later? First, they add a five-game playoff and then they add two potential games to each of those playoffs. And they have to arrange them for TV.
In 1994, baseball moved to a wildcard system in response to several years where many pennant races were (literally) over by Memorial Day. They split each league into the current THREE divisions and then let the team with the best record that did not win the division into an eight-team playoff. Now, they added a first round 'best of five' series....adding FOUR more series of five games each.
This pushed the World Series back from ending around October 10 in 1956 to STARTING on October 20 in 1996.
And then in 2012, they invented what I call the 'let's make sure Boston or New York makes the playoffs' by adding the 'play-in game,' where the second wildcard team plays the first in a 'do or die' match-up.
And that's the answer to your question. Baseball added four teams in the 1990s - mostly to pay off the settlement from the Collusion hearings (from 1985-87 the owners conspired to not sign free agents and intentionally keep salaries down).