Quite easily it's also to give more slack to re-accommodate those that DID buy J/F when their schedules get disrupted.

But this really is pathetic.

My JFK-LHR was 2.5h delayed last week - inbound had a mechanical in MIA. Moved to BA so I could make my connection and still attempt to arrive on time, but got stuck in a middle Club World seat. And it wasn't rebooked as an AA codeshare so now I have to request/fight for ORC because of big differential in RDMs (and EQMs) given expensive ticket.

Then return BCN-JFK 2.5 hours delayed the other day, also due to mechanical on inbound (apparently they had to sub that a/c after they left the gate).
Glad we got the CIP 763, and flight/crew/service was good, but come on.