According to Honest John (D T motoring supplement ) the problem is that most European car manufacturers leave the ends of the spring wire just as sheared, whereas Japanese manufacturers grind the ends so that, on a flat surface, the spring would sit vertical. This reduces the stresses in the springs.
A friend who is a great VW / Skoda enthusiast has had several springs break on his cars (different models ).
"If only everything was as reliable as a .."
The exception to this may be Renault. When we had Renault 5s, in 17 years, (110K miles each ) there were no spring problems, BUT the upper and lower spring seats were angled to match the spring, to minimise stresses.
In 12 years, of ownership, (80K miles each 
neither of our Toyota Yaris, had any spring or damper problems. The only parts needed were a set of brake pads, a set of tyres and a brake light bulb, each.
Where I worked, before retirement, although volume production, we tried to design in quality and reliability.
But we still had a sound aftermarket. A moral there, perhaps?
Howard
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