This might help players visualize season starting placements

http://na.op.gg/statistics/tier/

As you can see, roughly 50% of players currently ranked are in bronze. I cannot show a graph but at the end of season 5 and preseason there was roughly 20% players in bronze and 40-45% in silver. It is important to keep in mind there are still many players that are not placed yet. But this should helpful players visualize how resets work each season.

See how there are not challenger, master, and hardly any diamond players? Players dropped in rank and now have to rank back up.