The key issue here is:
a) Nissan acknowledged that there was a manufacturing defect.
b) I reported this problem to my dealer within the original 3-year warranty period (and I still have written evidence of having done so), but I did not know that Nissan had recognized the problem as a manufacturing defect, which they were willing to repair under warranty.
c) The (incompetent?) dealer did not know that Nissan had acknowledged the problem as a manufacturing defect.
d) Therefor, the dealer did not fix the problem, even though Nissan would have covered the cost of the repairs (under the warranty)
e) After the 3 year warranty had expired, I learned that the problem was an acknowleged manufacturing defect that Nissan had been willing to cover under warranty.
f) I point out the above facts to both the dealer and Nissan Canada, but neither is willing to help me.

The whole situation is totally ridiculous. I still own both my 2002 Maxima and the 2005 X-Trail, and I like both vehicles very much. Normally, if you have good experience with vehicles, you will be inclined to buy another from the same manufacturer in future. However, because of this stupid little warranty issue, my next vehicle will be anything but a Nissan. I can't understand why Nissan put me in this position - it makes no sense! Nissan loses my future business, and because I refuse to do business with a company that screws me, I lose the opportunity to buy Nissan vehicles that I like! Incomprehensible business strategy, Nissan!