Despite the visual appeal of their products, Apple normally does a very good job with prioritizing function over form except in this case with the charger wire being so fragile and thin. I know I'm not the most careful and delicate person in the world, but the failure rate here is ridiculous compared to other similar products I own. The end of the cable gets frayed every single time. Otherwise, Apple makes ridiculous…
I support around 300 Macs for work. In my extensive experience, the deal here is that people are FAR too rough and careless in winding up those charger cables over and over. Apple HAS implemented strain relief here and done their best to make the points of failure less vulnerable. Here's a tip: Instead of yanking the cable at a 90-degree angle and winding as tightly as possible, let the cable come out of the charger…
People aren't "FAR too rough and careless." People behave as people behave.
A high end manufacturer like Apple should be design and manufacture their devices to stand up to the rigors that people typically put them through.
Why doesn't Apple? Because their user base (or at least the majority of their user base who winds chargers too tightly, which I apparently fall into) would rather buy a new charger every year or so than switch computers.
It's quite profitable for them.
[Edit -- fixed typo]