Let's not kid ourselves that maintaining 10TB with resiliency handling and other controls built in is something that is trivial. It is only trivial due to the offerings that Cloud computing has made easy.
Self-hosting implies those features without the cloud element and not just buying a computer.
10tb fits on one disk though - it may not be trivial but it's not overly complicated setting up a raid-1. Off-site redundancy and backup of course does make it more complicated however.
You can buy a 10TB+ external drive which uses RAID1.
You can also buy a computer with this — not a laptop, and I don't know about budget desktops, but on Dell's site (for example) it's just a drop-down selection box.
Self-hosting implies those features without the cloud element and not just buying a computer.