If BA can profitably serve Tampa, Florida on a five times a week basis using the LGW 777 fleet, I cannot see why San Diego cannot justify a resumption in service.
I am here for a couple of days enjoying the sights, there are great restaurants, a lovely climate (70 degrees today) and the internationally famous Zoo as well as a great aviation museum.
The airport has a great low approach over the city, almost like Kai Tak, and is pleasantly small,
When direct service was withdrawn, many people reasoned with nearby service to LAX and SFO, SAN was not really necessary.
But BA fly to MCO and MIA (and Nassau) in Florida without a problem. And SAN is a great landing point allowing passengers to open jaw, returning from SFO having driven the Pacific Coast highway.
There are also some large law firms here which would justify business travel, as well as the flight being long enough for aspirational travellers (apparently that's what people like
fbgare called, although I think he has already surpassed his own aspirations

travelling only in FIRST now!) tp want to travel in greater comfort.
This has to be a credible potential for an additional route in the future - or should we wait for some additonal aircraft to avoid being substituted onto one of the infamous British Airways
emergency back up aircraft!