their 'J' was such a magnificent/superior platform to the trusted 'K'
Which it indisputably is. The idea that the 1960s variant was 'definitive' & no amount of technological progress could improve it is rather ridiculous although that was precisely what was spoken by many on the 'K', mostly navigators it must be said. The 'hot air' from the J crews was just to try & rebuff those ridiculous notions!
Anyway, such juvenile wranglings are very much a thing of the past & I haven't heard any such conversations for many years. The J has been in service for long enough & been the backbone of Tac AT for long enough for anyone to seriously challenge its credibility.
Just in case, I'm speaking as one with quite a few hours on both types over rather more years than I care to recall these days.