I get it but sample size I don't think is getting used correctly. Sample size would be all teams that have say a 20 game winner should win the WC because the history shows it to be a favorite. A 1 game win or go home scenario is pressure filled not because of sample size because in the context the sample means nothing. Does that make sense or did I lose maybe even myself with that?
Sample size means how many games determine who the best team is. Five or Seven games simply is not a large enough sample to make that proclamation. To prove this point, here is what the playoffs looked like on April 12th, when teams had played about seven games
AL
1. Baltimore vs winner of 4. Chicago vs 5. Detroit
2. New York Yankees vs 3. Texas Rangers
NL
1. Chicago vs winner of 4. Cincinnati vs 5. Pittsburgh
2. Washington vs 3. San Francisco
Clearly a sample of seven does not offer the same accuracy as a sample of 162 at determining who the better team is.
Also, being a good team for 162 games is completely different than being a good playoff team in a seven game series. Classic example of that: the 01 Diamonbacks went 51-18 when Johnson/Schilling started and only 49-52 when they didn't. They went 9-2 in the WS when Schilling/Johnson started and 2-5 when they didn't. The ability to use high value pitchers in situations in the playoffs changes how good teams are. The Diamondbacks were a "92 win" team in the regular season but in the playoffs, they're almost impossible to beat.
Think of the Cubs and Chapman. In the regular season, you have to worry about multiple innings or multiple days in a row but in the playoffs, you get so many rest/travel days that your bullpen can just be maxed out every single game in a way a regular season game you cannot.