Each bank has its own priorities - invest in customer acquisition sometimes, cut expenses sometimes, increase fees sometimes, etc, etc. For public companies, their priorities are often out there in annual reports or shareholder meetings. Amex in particular went from aggressively acquiring customers to increasing their efficiency ratio, ie regrouping and cutting costs, increasing some fees, and focusing on retention. Chase too, it is the trend du jour at a bunch of Banks lately. There are exceptions - Discover and Cap 1 especially still see opportunity in acquiring juicy customers.

When a Bank wants new customers, offering incentives is a great way to get them (credit cards, checking bonuses, etc.) Every bank will dip their toe in the pool when they need to. It works. Chase and Amex will get there again at some point once this current phase gets the results they want. Now, there probably won't be as many suicidal techniques allowed like signing up for 9 of the same card on the same day, but Amex will certainly embrace old customers again when they are ready to focus on that.