I'm going to honest.
Before disc drives became the norm in gaming consoles, backwards compatibility wasn't generally needed. Cartridge based system had less moving parts, which as a result meant less wear and tear, as we have all seen, with some of us owning working consoles nearly 30 years old. With disc drives, there are more moving and delicate parts, meaning things generally live a short life span. When hard drives where introduced into consoles, there life span was cut even further. Corrupt files systems, bad sectors, the list goes on.
When production stops of these consoles, were royally screwed. It's a matter of time until the games we own are nothing but fancy tea coasters.
How many PS1-2-3's have you gone through? Personally I have been through 7 between the three, yet I still own a Sega Mega Drive that is over 20 years old, and a N64 that is over 15 years old.
I have been lucky with my Xbox 360, but how long can I expect that to last? I can assure you that I'll be buying another one before the Xbox One comes out. I'll keep it sealed and boxed until my first one eventually presents me with the dreaded "yellow light of death".
In the age of disc drives, backwards compatibility has never been so necessary.
Back in the day, cartridges where outshone by discs, due to storage, cost, and the amount of memory a disc can store over a cartridge, now days, there's little to no reason to start using cartridges again, bar the cost factor. Generally a 100gb Sony cartridge would set you back 66 euro, with a game on top of that, that's 100 euro minimum.
By the way I'm not saying we should start using cartridges again. I guess I'm just thinking out loud.
With a Blue Ray discs holding a maximum of 25gb per layer, I would reckon a 10gb cartridge would hold the average game, and leave enough storage to hold a few save files. If you look at The Elders Scrolls V Skyrim, the game as I understand takes up 7gb (with mods) on a hard drive. My save file after 211 hours and completing everything wasn't much more than 15mb. It could work?
You could then argue that hard drives would become redundant, therefore removing them from consoles, and therefore cutting the costs of production, but then again, you have to look at how important digital downloads are, and how much you want to offer your customers, but does a gamer really want to use the PS3 or Xbox 360 as a storage device? A dumping ground to photo's and video's that you'll never likely look at? If your using a computer, you likely have an external hard drive, a hard drive that is likely over a few hundred gig's, if so, you already have a perfectly good dumping ground.
I think digital downloads are important enough to have some sort of method for downloading a game or what not onto a built in storage device, but are they important enough to warrant a hard drive? Would a memory chip or flash drive not be enough, with the ability to copy the files over to an external storage device? Of course you could argue that you would then have to spend money of a FAT32/ NTFS/ EXT3/4 formatted hard drive, but would that cost not be worth it, considering you are less likely to have to buy a new console *IF* there wasn't an internal hard drive, and *IF* the system was cartridge based.
Any of you who have no idea how a hard drive works, probably missed my point there.
As I said before, this isn't something I definitely want. I'm just thinking out loud. The mumbling's of a fool really.
EDIT: I'm well aware that a lot of faults with current gen consoles are due to the heat generated by the CPU and lack a sufficient cooling method, and that the thermal compound Sony and Microsoft use is crap. You can help this by replacing the existing thermal compound with a decent quality paste. You would be surprised by how much this actually helps.