I believe reparaibity is also about availability. In a way, like Miroslav said, having very fragmented brands will make it less likely to find parts.
Take a MacBook Pro. The classic one with DVD reader built-in.
That would be the most repairable in my opinion since almost everything is detachable from the board.
Enters the display cable for that model, or the LCD: break them and you have to remove the glass from the frame to replace them. Very very few PCs will require that.
But since Apple have been using the same form factor for that model since at least 5 years, you can find every single screw, bracket, cable, and part second-hand. And parts manufacturers/suppliers find it economical to manufacture, stock, and supply parts. They may be expensive, but they are available.
Take that L50 Toshiba with touch-screen. My client paid for it circa $1200 and broke the digitizer. The distributor wants $450 wholesale for it. It's just a piece of glass that I can't seem to find in any other place. I have a Toshiba P45t with the sme issue. On the other hand, Sony digitizer for an expensive model is $25-$40, available everywhere on eBay and in China by the piece.
My point is, if models are popular, not fragmented, and their form factor not changing a lot every year, and a bit expensive, it will be easier to source for them parts and find people who fix them for reference. Keep that in mind.