Delta has problems because their operation isn't actually better than anyone else's, despite the lies they feed the public and their employees. They do things like beefing block time to make it appear better on normal days.

When **** hits the fan, they can't keep up.

Meanwhile American causes its own problems with things like unrealistic connections and underblocking the schedule. This block time increase and spreading out more banks will help solve the problems the airline has created for itself.