Why is the PS3 slim such a big deal to everyone?

[JEDE3]

kn - isupply estimated it at 840 to begin. Sony in may said they lose 10% per ps3 sold. 10% would mean it would be about 420. 840 - 420 = 420. And the R&D is most likely already paid off. It's ridiculous to think that Sony isn't doing this for the long run.