This is not as true for the Mac Mini, not even the latest generation. Although not plug and play, the hard drive in these machines are serviceable with a basic

This is not as true for the Mac Mini, not even the latest generation. Although not plug and play, the hard drive in these machines are serviceable with a basic kit you can buy off eBay and clear instructions from iFixit. The Mac Mini referred to in this post moreover is 'over six years old', making them a little easier to service.