>"The more interesting question is why would so many thousands of people in a big firm seemingly be fine with frustrating customers and giving the appearance of a gaggle of clowns?"

Existing in a large org over the long term becomes a game of survival. It's very much similar to the "dark forest" or the Eye of Sauron. Your number one goal as an IC is to complete the tasks directly assigned to you by a supervisor and avoid at all costs any kind of "hey you" assignments that have zero upside and plenty of possibility for downside. It would be wonderful if we lived in a world where individual initiative mattered and was rewarded, but it doesn't. It becomes "why haven't you delivered XYZ", and the vague ephemeral reasoning of "well A, B and C for team D needed fixing" is not an excuse, and now you can't pay your mortgage anymore.