When you piss off a cop, get arrested, and are released a few days later, without any charges, you also have exactly zero recourse through those checks and balances.
When you piss off a cop, and he brutalizes you, you may get some recourse (through a lawsuit, unlikely as your case may be), but it does not serve as a deterrent to subsequent police misbehaviour. (As we have seen over the past summer.)
As an upper-middle-class office worker with flexible hours and cash to spare, even pursuing a small-claims case was a major PITA for me. Took a ton of time, effort, and money.
For those who do go to trial, the right to a lawyer is often pretty weak support. Public defenders are grossly underfunded and overworked, and there is no guarantee that they will be competent or committed to the case.
A jury of ones 'peers' is rarely the case either. Yes, they are citizens, but they are rarely of the same background, ethnicity, or social status. They are hand selected by lawyers to remove people that might be sympathetic to your plight.
I've never heard that jurors are the best and brightest among us. Often the highly educated and analytical are removed from jury pool.
Police suspects you have committed a crime, holds you in jail until trial or until you pay bail and may never end up releasing you even if you are innocent.