Generations do not equal years. There could in actuality be several generations released within any given year. Your quoted text makes no mention of years, so your perception of the quoted logic equating to years is flawed.
You need to see it in the context of the discussion mate. The original claim he seemed to defend was that the iPhone 4 was 4 years old because it was 4 generations old
Anyway it doesn't matter, I was actually being dumb and not going past the first page of the discussion, hehe. Move along!