Preconfigured mirroring (RAID1) on every PC with 2 disks
Every Desktop and Notebook which has at least 2 disk slots should be optionally availible with preconfigured RAID1 managed by the motherboard RAID controller
The obvious objective is to almost transparently survive disk crashes for casual users. Reinstalling after a crash si a several day long nightmare, even if you have backed up your data , which is itself a nightmare, considering these data are spread everyware.
So most casual users do nothing and live with this sword of Damocles hanging above.
SW RAID managed by Windows is not an attractive option; not available with basic XP, difficult to setup.
HW based RAID preconfigured at BIOS level is transparent and relatively easy to live with.
Wasting 50% of disk space is not a problem with the tiny GB price we see today.
Preconfigured RAID 1 exists in Dell line but is limited to very few high end workstations and servers.
Please see mano_g's comment