Delta messed up. Again. 1991 when Delta took over Pan Am domestic routes after the latter had sold international to United, those of us who were lifetime Clipper Club members were sent Delta Crown Club (now Sky Club) membership cards with a letter from the Delta CEO welcoming us, then stating that the lifetime membership was no more after April 1992 meaning we would be charged annual dues for club membership.
That lasted about six months when they realized what a bone headed decision they had made. I still have cards for both, although Delta never could replace Pan Am. Remember that they neglected to change their name to Pan Am at a time when everyone in the world knew it was the American international airline going back half a century plus. No one in Tokyo, London or Rio had much regard for an old south airline from Georgia.
When Delta merged with Northwest I was a lifetime member of the NW Worldclub. Must have learned lessons from Pan Am as I have lifetime membership in the Skyclub.
But last time I used the club it sucked, it was so crowded that it was difficult to find 2 seats together for my bud and I. And then I needed a ticket cancelled and was told they no longer did that in the club I had to call the 800 number, total crap. I complained to Delta and the phone customer service rep did not believe the club could not support my ticket change, she was flabbergasted to find out it was true.