There is of course a point at which a repair becomes more impractical than a replacement, but with a good bit of patience and a steady hand, even an amateur repair tech and breath new life into a broken computer.
The idea of "fit for purpose" is pretty important, especially with electronics, as it's easy to get lost in spec competitions when considering the repair or replace decision. When I did Tech Support for a University and would have students bring me broken machines, it was always a personal consultation to determine the best approach for the student. Often they had little or no money to put towards a new machine, and most of the time all they needed was something to write papers on and watch netflix/do facebook-ey things. A newer computer would certainly do all of the above better, but that doesn't mean that first machine couldn't also do it just fine. $80 and an hour of my time to replace a cracked screen beats the student having to spend $400+ on a new laptop.
It's a weird, fine line with modern consumer electronics depending on what is broken - if you can clearly tell what the damaged part is and a replacement less than 1/3rd the cost of a new machine, I'd suggest it's worth investigating the repair option.
Also, the Nexus 5X is out, almost identical, but based on the LG G4 instead of the G2, and has a small handful of niftier features, including better battery life.
Electronic components generally don't wear much, there's nothing that makes them unsuitable for use in new devices except that ordering new parts is probably cheaper thanks to economies of scale.
Come to think of it, maybe it could be changed? Recycling electronic components is mostly about melting the elements off the PCB and then sorting them to correct bins; the latter part is what usually involves humans. With proper design and sufficient automation, maybe there could be a fully-automated recycler that takes random electronics junk as input, and gives out spools of components ready to be used by a pick&place machine?
Certainly compared to clothing electronics do tend to become obsolete but it obviously depends a lot on the electronics and what they're being used for.