Also, I disagree that the modern economy is unregulated. Quite the contrary, in fact. And it's regulation, bailouts and crony capitalism that protect companies who make awful products.
The profit motive covers (a).
This is a big reason Apple is the world's largest computer computer company despite charging more for the same transistor counts. People are actually willing to pay a huge premium for reliable stuff that they don't have to junk after a year. The market gets it right.
[0] https://www.google.com/finance?q=NASDAQ%3AAAPL&fstype=ii&ei=...
I'm talking about my mom's 1957 Ford pickup that still runs great today. I'm talking about the Ostrisizer can opener from the 1970s that my family still uses in their kitchen. 5 years lifetime for a $800 product is not "built to last".
Oh but you're talking about pickup trucks and can-openers. Oh ok my bad.
Were those created by socialist / communist economies now?
What are we even talking about here? Did capitalist economies develop these things or not? Does the profit motive not motivate the auto company and can opener company to produce a better product?
Capitalism _could_ produce products (even high-tech products like phones) that last for longer than 2 years (e.g. swappable chips/boards/screens, etc), but it doesn't, because the rapid, constant growth demanded by investors is antithetical to making products that are built to last.
Not quite that exact combo, but you get the idea: https://www.youtube.com/watch?v=fPF4fBGNK0U