I think you're wrong on both points there. Both PS3 and PS4 were initially sold at a loss. Money is made back from PS+ subscriptions and games.
And it's likely the drive will be 1TB SSD with no HDD. There's no way a gaming system can keep copying stuff from SSD to HDD to SSD without some kind of performance penalty.
What if I decided to play Title A which is installed on the HDD. "Please wait whilst we get this game ready for you." The game starts copying essential files from HDD to SSD which make take a couple of minutes. That's a couple of minutes too long.
Then after five minutes of playing Title A, I find it a bit boring and decide to play Title B which is also on the HDD. So Title A has to be copied back from SSD to HDD and Title B from HDD to SSD. This is going to take what seems like forever.