That's my birthday!!
Some of it is perfecting new technology - you're seeing new tech in transmissions for example like continuously-variable transmissions, higher numbers of gears, and dual-clutch transmissions. As with anything else, testing only goes so far. Once they get out in to the real world new issues are discovered, revisions made, and things get to a pretty stable state. New regulations/mandates/whatever come down & the cycle repeats.
Other times its manufacturers trying to find a cheaper/easier way to do things, sometimes as a cost savings measure, sometimes to save weight.
If you wanted a basic car with no tech features, spartan interior, and were happy with getting 10-15 mpg I think most manufacturers could build something absolutely stupidly reliable. It's all the 'new' stuff we want that causes the issues.
Well stated sir