In some ways the incentives of Athenian democracy were not as bad as modern democracy. Most of the offices were held by lot rather than by vote, and the office held by vote - the strategos - rotated from day to day between ten strategoi. In addition, at their end of their term, every magistrate was examined for whether they performed their duties well and if they were found to have failed to do this, they could be taken to court and be personally punished. At least unpopular measures could not carry, which isn’t necessarily the case in modern democracy.
Of course, as in modern democracy certain features led inherently to demagoguery. There was of course the election of strategoi, but also just the populace voting on measures in the Assembly could obviously be corrupted (but is an elected oligarchy that much better?). The long Peloponnesian war likely had much to do with the latter features, with demagogues seeking to extend the war for their own glory and power, at the expense of the polis overall. There is, of course, the corruption of the courts also (e.g. the trial of Socrates), and Athenians appear to have had a strong inclination towards statist law from the earliest details we know about their law (perhaps a result of codification, e.g. by Draco) - in contrast to the Romans whose law is much closer to common law.