No - not nostalgia. Just well-developed backs, to provide some encouragement not to neglect "the back view" when training. Lats to the fore! A few training tips too.  

No doubt at all, guys are better wised up now about showing off their back-muscle development as well as their chests and abs. Much to be complimentary about here. Pull-ups are great for working the back muscles:   ...as are cable pulldowns...   So is rope climbing:  ...in fact, just climbing anything is great too: