I think you've been here long enough to remember back in 2012-2014that that's exactly what Tesla did. You could add free unlimited supercharging as an option to any non-Performance Model S (S60 or S85) for $2000. It was "included" in all P85s and P85+ models (meaning the $2000 was added onto the price and you couldn't de-select it). There are threads about it here talking about how the $2000/car is more than enough to build out the SC network and pay for the juice.
Back when the Newark, DE SC was the only SC in the region and had only 4 stalls, almost every time I stopped there while traveling through there was a local guy there charging his car. Even when it was full and people waiting, he didn't move.