Epicurus notwithstanding, there are limits, mainly fiscal ones. A technology (or idea) may exist that will prevent all mistakes and defects in a given process, but be too expensive to invoke. We still have to make money. This isn't to say that we shouldn't be on the lookout and be open to new ideas, but facts is facts.
Please permit me to disagree with your views on limitations. Imagination can do miracles. Did you get a chance to see the thread "Sixth Sense Device"? Pranav Mistry has come out with the 'Invention of the Century'!! He permitted a free flow of imagination and persistently worked on his idea and vow! with his invention we will totally change (for the better) the way we work today!
2. I smell your obsession with the notion, that 'Error-proofing' is always expensive (with due appology, if my assumption is wrong). In another thread also we have exchanged views on the subject, and I re-iterate, that one has to select a cost effective poke-a-yoke from the wide range of available options. The range widens, if you let your imagination flow without restriction.
Another important point is, how you compare the cost-of-poor quality/rejections/rework etcetra vis-a-vis the cost of error-proofing. Let me quote a recent example from my factory. One component 'X', for export has nine operations. Inadvertantly, one minor operation was missed and 75000 pcs were packed, and sent to the ship-yard. As a policy matter we always retain a few samples from every sent lot, and one sharp fellow chanced upon to check the samples, and noticed the missing operation. Immediately we asked the lot to be quarentined and brought backed to the factory, reworked, re-packed and re-sent to the ship-yard for export. I leave it to you to imagine the huge cost we have suffered due to one small mistake.
We immediately brainstormed to come up with the ideal (and cost effective) error-proofing. A couple of days ago we installed nine fixtures with sensors & dial gauges on the last machine. The operator has to pass the finished component through all the nine and the machine will not start untill nine green indicators flash on the panel. Besides error proofing, this also saves inspection time.
Hope this clarifies the reasons, as to why I strongly advocate for error-proofing.