Maybe in your country but in many, many places in the world this is demonstrably not the case.
as with markets, idiosyncratic conditions like sociopathy can lead to pockets of undue concentrations of power, no doubt.
but it would be even worse if those same conditions were concentrated on and elevated to wider populations. by distributing power, you can more effectively pit one against the other, and have some chance of bettering conditions over time. those chances decrease with power concentration.