It's simple. Allow quads in SP for ladies.
The first men's 4T was landed in 1988. The first quads allowed in the short for men was in 1998. In the few years around then, there were at least 12 men (rather arbitrary number; true number probably much higher) attempting quads. Right now, there are only three women that are attempting quads in seniors, maybe a few more by the end of the season. Also, women have been consistently landing quads in competition for about two years, compared to a several decade history of landing triple axels. It would certainly go against precedent to allow women to do quads in the short right now, when that would benefit so few skaters.
By all means, allow them after the Olympics, when you'll likely have a good 10-15 women attempting or landing quads. Otherwise, I'm not expecting the ISU to change their rules on this one just yet.