Agreed. The issue we seem to forget when discussing these issues is that there will always be a bottom income quintile, and that it will always be populated by

Agreed. The issue we seem to forget when discussing these issues is that there will always be a bottom income quintile, and that it will always be populated by a full fifth of the population (not the few deviant outlayers they make it out to be). If just 20% of those at the bottom were already there, it means 80% fell there somehow. Imagine the economic stagnation and nasty social dynamics that would happen if (the perception of) a single mistake or transgression would ruin your life!