The Kitty Hawk did have the major mid-life overhaul, it was the JFK which didn't. Besides, they need to retire the Kitty Hawk to free up an airwing for the GHW Bush which should be commissioning in a couple of years.
KENNEDY did but rather than use Newport News Shipbuilding Dry Dock they sent her to Philly about the same time the old yard closed down. It was a rush and botched job as a result. Only two east coast yards do good carrier work and both are in the Tidewater area NNSBDD and Norfolk Naval Shipyards right up the river from NNSBDD.
AMERICA was the one who missed getting the SLEP overhaul and as a result it had a major explosion upon return from a third six month deployment in three years time in March 1994. Poppy/Cheney did it to her twice and Slick Willie/Aspin did the third and next to the last one. She was deliberately ruined there was no excuse for it. It was band-aid repaired after a Cold Iron {Dead in the Water} tow up to Norfolk Yards then sent on a last cruised and decommed in 1996.
There's a lot of rumors floating around about the AMERICA and JFK that weren't true. One of them included the rumor that they were to be CVN's and McNamara changed the plans. Simply not so. Ike ordered AMERICA and her keel was laid before JFK took office. At that point such a change is impossible to do.
Another was a rumor of a thin or weak hull due to steel shortage. In the early 1960 the USA had lots of steel to spare.
It is possible Kennedy may have been intended to be CVN as Kennedy is another class carrier in itself and McNamara would have had more say in it. AMERICA was the last of the Kitty Hawks and always intended to be a KH class. I think the AMERICA nixed being a nuke rumor started because there was a set of blue prints I remember seeing myself on the ship that had a Typo on them. It had CVN with a line through it and CVA-66. They were in Engineering Central Control.