Manufacturers that put more than, say, 0.001% "broken" parts out onto the market should immediately be forced out of business.
come on, that would be too costly, (testing costs will be passed on to the customer) I'd say I'd agree with you if it was 0,1% (one in thousand)

If you use a part that works only under the circumstances under which you require it to function, aren't you concerned that the "broken" features are an indication that the device itself is defective?

I see absolutotally no reason to be concerned with whether a part can do something I do not need. I use the SILabs f12x parts becuse of their speed, they have tons of analog functions, why would I worry about (testing) those - I do not use them.

I have had, when working at the bleeding edge, to work with defective parts known defective where the defect was "workaroundable" (sorry bad word/grammar) and also parts with known defects that did not affect my project. (just look at final errata for first spin parts)

That's why I don't buy cars made by FORD, GM, or Chrysler
If you bought one of the above and the gas gauge did not work, would that keep you from driving?

Erik