Having a peaceful mandatory transfer of power from any individual after a set number of years is not the only requirement but it's one of the most fundamental. China has removed that. The US for all its problems still has that, despite the troubles during the most recent election.
A democracy that has been subverted by corporate interests and is not acting in the best interests of its population still has mechanisms in place by which the population can detect and change such subversions. The forced transition of power being one of the most important.