Here's a data point for you.
Just traded in our 2018 Model X with 92,000 miles. I used Teslafi from beginning.
353 S/C charges
13,1498 kWh
Approx $4,319 savings over the 5 years.
I think the price of S/C charging will continue going up from here but I felt saving less than $1,000 a year was...