I presume that the premium flight operates at 21:30 because the red eye gives on a full day's work in SFO and even a cocktail meeting (if such a thing still exists), while not killing a work day traveling. Moving the flight time likely preferred by HVC's to meet a lounge schedule seems a bit backward, particularly because the crowd that can pay for F/J are also not likely overly-bothered by having to buy a cup of coffee among the common people. While none of us have access to marketing data, I have to presume that because SFO is not an AA hub, most passengers arrive at SFO in time to make their flight and not hang around for a well drink.
Yes, it would be nice if the AC were open for the 21:30 departure, but I can't really see expecting any carrier to bring in another shift solely to service one flight.
In 2024, when the industry hopefully recovers, this ought to be on the punch list.