Sure PS1, 2 and 3 had a good media solution that on the case of Nintendo competitor made several 3rd party go exclusive to them (besides Nintendo relationship being bad at the time). But the buy of the console for the use to hear CD or buy DVD and BD were minimal.
Haven't said no one bought PS2 or PS3 for those reasons, but that was a very minimal quantity that nowhere would really change the quantity of consoles sold.
How can you say that with any amount of confidence though? At launch the system was constantly praised for it's Blu-Ray capabilities. It was the CHEAPEST Blu-Ray player on the market at launch, and for a good time afterward. Not to mention it was the only Blu-Ray player at the time that could also get bonus content from the internet.
This was all when HD TV's were starting to pick up sales, and before streaming. Anyone who decided to upgrade to an HD TV was going to get another HD companion device, and Blu-Ray handily beat HD DVD. If someone was looking for a Blu-Ray player and noticed that the PS3 was $400 cheaper with MORE features than the competition you bet they'd be choosing that device. Especially since many people were stating that the quality of playback surpassed those of other Blu-Ray players on the market at the time. So: cheaper, more features, AND better quality?
Less people purchased the PS1 as a CD player (though it was a great CD player at the time too), but a lot of people did actually purchase the PS2 and PS3 for their multimedia capabilities.