Well you are right but only half. Football is always full of surprises and everything can happen but let's take Bayern.

CUP - Doing just fine so far!
Champions League - Only 1 big surprise.
League - Doing perfectly just 2 surprises thanks to Pep experiments.

So in 40 games they got 2,3 big surprises and results like Porto - Bayern for them are once at few seasons not so often like in Top Eleven.

Nobody is complaing just because of one bad result, the point it and we have to admit it, there are to many bad results per season in Top Eleven, ofcourse not for everyone.