Like I said in the other topic May 2002 was the month of a price drop for the Ps2 the new price was 199 dollars (previously 299 dollars) Thats why ps2 numbers are so high.
Plus the Ps3 had many price drops and the last one was in novemeber 2007 for the 80GB (399 dollars)
The Ps4 has still the same price that at the launch.
http://money.cnn.com/2002/05/14/technology/ps2_pricecuts/