Except you always expect the better team to win.
now if you watch traditional sports, (for example football). you will see enough examples where the better team *loses*. it isn't always the best team that wins.
that does not mean the person who did win is a fluke, or should not deserve the win at all.
The flaw in your logic is also, that you put quantity of wins over quality of wins.
if you lose from for example FaZe in the upper bracket, and then in lower bracket beat up 3 Bo's in a row; MIBR, Grayhound and Fluxo, then arguably you are more consistent, but in reality you beat way weaker opponents.
It does not really matter at what point you define how you are satisfied, in reality it's all probability and who shows up what day. and if you are satisfied with the result or not, does not influence the outcome at all, only your own perception.
But it is by all means a false perception to think single elimination has more risks for upsets than a system with a lower bracket- the probability stays the same. the probability of it ocurring multiple times only becomes less, since there are more chances. it doesn't mean there is a higher chance of an upset happening.