When I see "it's hard to beat a team 3 times in a season" I always think of the Bill Burr quote when he talks about the stat that most shark attacks on humans happen in shallow water. Of course that's where they happen because that's where the people are. Of course it's hard to beat a team 3 times because it's extremely rare to be 2-0 against a team and meet up with them a 3rd time. The saying that it's hard to beat a team 3 times insinuates the 2-0 team is going to have a hard time winning that 3rd game because they won the first two. That's just not true at all.
Well, maybe you don't really understand BB. Mental is so much of it. Also by the 3rd time, opponents learn tendencies. Add to that we all get more lazy the more familiar we get at something. Yes it's rare to be 2 and 0 and meet a 3rd time. With the BIG and a tourney, not exactly rare. HS in regions.
There is also a mentality that comes. The 0-2 team can really come after you and your thinking, not a big deal. Teams don't stay static, they change throughout a season. A well coached team not great changes the most. Teams moving through a season well, don't have as much reason to change.
An example is W Burlington BB this year. They are pretty good. They beat a highly ranked small school pretty soundly, then turned around and lost to Fairfield which was movitivated. Next game WB beat a pretty decent Burlington...smoked them.
It's the same principle as the original premise. I know from experience that it is just plain hard. Being really good and dominant over another team, even the opponent's team manager is in your face.
Several years ago, my son played on a really good BB team that finished 2nd in conference. The champion team had Bates-Diopp. 1st game we were shell shocked. 2nd game was a barn burner but lost. Didn't get to the 3rd.
What was interesting was the 4th place team one a state championship. They had Nick Norton who ended up at Drake (Randy Norton's son) and before a knee injury his soph year was a high level recruit and signed with Creighton. Anyway, the first game with my son's team Norton and Co put 42 up on my son's team in....the first quarter. Next time (I"ll brag... they put my son on him) and we won. Same team, mentality and circumstances change. Norton wasn't used to being hawked all over the court. The team adjusted. Fans in the stands or on TV especially just can't take in the nuances of a game that change things radically. BB in someways is easier as you only have 5-7 players to study that can really hurt you. The more familiar you are, the easier you can impact the opponent. The "better team" just isn't as motivated.