Maybe the rot set in when they lost Costco ...
"Costco Cards Account for One Out of Every 10 AmEx Cards in Circulation" - WSJ
https://www.bloomberg.com/features/2015-how-amex-lost-costco/
https://www.fool.com/investing/2016/06/22/how-bad-management-led-to-american-express-costco.aspx
http://viewfromthewing.boardingarea.com/2015/10/15/an-inside-account-of-how-amex-lost-the-costco-deal-and-what-it-means-going-forward/
But wait sports fans, there's more Interesting keynote by Billy Beene (Oakland A's EVP) On stats, the background to "Moneyball", and hanging with Brad & A.J.
If he could remember he wanted to shut it down. Oops! https://www.nytimes.com/video/us/politics/100000004820721/rick-perrys-energy-department-oops-moment.html