I like the flexibility of single fleet. Any flight, any domicile, any destination. Bid any open trip in your seat. Trade any aspect of the job (trips, training, vacation, etc) with any other pilot. ETOPS degraded that slightly.

There’s risk with those once in a blue moon fleet issues, though that’s only partially mitigated with multiple types.

I imagine the cost savings to the company are substantial with respect to training, maintenance, compliance, operation procedures, dispatching, network planning, cost estimating, scheduling of A/C and pilots, ground support equipment, etc. All in addition to the shared knowledge within the company of how to operate the single type for profit. For those reasons, I think it will take pretty substantial investment and work when we finally are forced to either diversify the fleet or move on to different single type.