Not sure what your point is - I'm guessing it's that Nike's warranty is better than NB's, because you can two-for-one for the rest of your life.
If so, that's a reasonable opinion.
I don't wear Nikes - I wear NBs, because I have narrow feet - but I take it from your post that the Nike outsole warranty is 6 months. If you can wear 'em out in 6 months, you can get two-for-ones forever. I'd agree that that's a good warranty. If you can wear 'em out in 7 months, I'd say it's worthless.
My understanding of the NB warranty is if you are unsatisfied - at any time - with the durability of the outsole, you can get a new pair. Since your satisfaction is (obviously) subjective, the NB warranty theoretically can be "cashed in" by anybody who buys a pair. On the other hand, the Nike warranty can't be cashed in unless you can burn 'em in under 6 months - which you say isn't hard, but I'd guess only applies to a tiny fraction of Nike's customers.
I'm going to go out on a limb here and guess that there's a higher markup on Nike shoes as well, making the two-for-one a more palatable business deal for them than it would be for NB.
Still, if the Nike warranty works better for you, great. I'm not sure that that quite proves that the NB warranty is a scam, as the OP suggests.