Thats like saying Xbox360 only reached 85m+ units because of ~30m Red Rings of Deaths, killing the console.
No, that's actually not the point of it. It was more about a thesis that claimed that an estimated 130 million PS4 sales were a more remarkable success than 150 million PS2's. At the time of the release of the PS2, the first DVD players were enormously expensive, which is why several million units of the PS2 were supposedly sold off due to the DVD function alone.
The PS4, on the other hand, offers no added value, relative to today's standards, than the one to play.