The Tesla superchargers loose big money. Not only the upfront cost to build them, but also the electricity prices do not account for the "demand charges" that they pay. It would be like if a gas station charged you their wholesale cost for gasoline with no markup to account for their salaries and fixed costs.
Tesla buyers are also mostly former ICE owners at this point, and so Tesla is not specifically competing with VW and GM in some "EV market". Elon has said this, and is very clear that their competition is versus gasoline cars.
I think that it is probable that someday, Tesla will move all their cars to CCS. It is a costly move though, as they need to retrofit their superchargers and it will upset all of us who have installed or own their proprietary chargers. They did do this in Europe.
If Tesla was starting today, then they would likely use CCS, but remember that they are not starting today, and that they have millions of cars on the road in the U.S.
It does not make sense though to install 2 ports onto the car, it is a waste of space.