I think the question is what does Tesla charge for non-Tesla as companies like Electrify America charge. If it is close to the same, I think they'll flock to SCs. They way they have jacked up the SC rates, last time I traveled over 1k miles, one way, I just said the hell with it and rented an ICE minivan. I think it cost me less for fuel than I would have spent for electrons. It was an efficient hybrid van.
The rental cost was pretty cheap at $35/day with my corporate rate. We had more room which was nice. I spent a fair amount on gas for a long trip but with my S, my greatest cost per mile isn't electrons, it is tire wear. Based on my last set of rear tires in the S, I actually saved money on this 5k mile trip by renting.
Here is an interesting article anyway for the using non-Teslas at SC and the cost and charging times.
Tesla has made some of its Supercharger network accessible to non-Tesla Electric Vehicles. Consumer Reports auto experts tried it out with three non-Tesla EVs.
www.consumerreports.org