The thing is, yes, darning is a massive pain in the arse. I think the majority of people would rather just buy a new pair of socks than spend the time repairing something so cheap. That said, I find there is something very satisfying about taking a hole and essentially reweaving it into a new fabric. There is also something lovely about how truly unique the construction on each pair of socks is - something I would never have noticed had I not started doing this. I know, how different can a pair of socks be (aside from the obvious colour and pattern differences)? But take this Calvin Klein sock above, it's stitches are a lot tighter than say the grey Reiss pair pictured at the bottom - it makes it much harder for me to run the stitches through easily. The fibre content is clearly different too - something not so noticeable when you put them on, but somehow very evident when you're working on smaller scale.
I'll be honest though, a very large part of the appeal of this new pursuit lays in the fact that I get to use this lovely vintage darning mushroom I bought on eBay. Isn't it a thing of beauty?