Self-interest is intrinsically self-liquidating on a systemic level.
One enduring if rarely stated principle of Neoliberal Democracy is that the single-minded pursuit of self-interest magically produces an equilibrium which serves everyone’s interests well enough to avoid the destabilization of rebellion or systemic collapse.
The problem in representative democracy is that every instance of waste, graft, fraud and monopolistic racket is somebody’s fat paycheck or government contract.
Promising good governance guarantees a losing campaign for public office. The central irony of representative democracy is similar to the central irony of capitalism: the relentless pursuit of narrow self-interest ends up eroding the shared foundations every self-interested participant relies upon.