A tie rod end is a ball in a socket to allow some movement since a wheel is moving up and down as well as side to side. In time they simply wear and usually "loose" steering is the result. Since the wear is gradual many drivers simply don't notice until the steering is so sloppy it is hard to control the car safely or it is caught in a "visual" inspection where a mechanic see's too much "play" in the tie rod. When you consider some severe shocks and jolts that go through the suspension, the life of a tie rod isn't easy.
Not the norm for it to break completely, but it happens. Could have been a substandard part in manufacture, or under designed for the weight of the vehicle, or simply just broke with no real reason other that its time was up.
Since one broke, I'd recommend changing the other side now too. They both lived the same life and you don't want to go through this again. As far as maintenance this not a maintenance item. So a quickie lube place wouldn't even look at it. Most mechanics tend to look over the front end and shake and poke around a bit anytime they get a car on a lift, but not all do this anymore as many shops have mechanics on a "clock" and push for productivity. Does your state require yearly inspections of vehicles?