@Polygon You are 100% right. 2TB should be the standard drive... especially for the price. I'm sure the companies would receive a good discount with the quantity they pull. However, 2TB 2.5" SATA drives are still somewhat pricey. Price per GB is only $0.04 for 1 of the drives - 2TB Western Digital Blue 5400RPM. Not sure how they would perform in a PlayStation 4 though.
Sony or Microsoft would get a bulk discount but since they're not free, the cost still adds up. Let's say they can get 2TB drives at $20 a pop and they ship 200,000 units with those. That comes out to $4,000,000 just for those drives.
And then let's say they get 500GB drives for $5 each and ship the same 200,00 units. That only costs $1,000,000. Even with discounted prices, the margins are much different.
That's probably why Sony allows you to upgrade your own drive just so that they can save money.
@CreepinDeth I didn't realize they capped it at the Kernel level. That's interesting - It makes sense to provide a consistent experience. However, it limits the upside potential for those who want to upgrade... which sucks a bit.
Yeah, I'll see if I can find the articles on it. Makes sense in the long run. It's probably also there to help keep the drive from wearing down quickly.