Other companies (Ionity, Polar, Instavolt, engenie) are ramping up their deployment of >100kW charging infrastructure too, which will be some relief for the superchargers.
I'm doubtful ... what with other EV brands appearing (well ... I thought that VW would be, but they've clearly shot themselves in both feet, so smoke-and-mirrors only from VW for another 6 months at least ... maybe 12 ... until they actually get the software issues resolved ... can't understand why Lying and Cheating wasn't the answer this time too ...
So my view is that a) other EV brands will be clogging up 3rd party chargers; b) chargers, or cars, will be slower-to-charge so dwell-time will be longer than at Supercharger and c) 3rd party charger companies have nothing else to offset cost against, so they have to make money, so only rolling out a few stalls at each site - which will just exacerbate the problem.
My perception (no data to back it up) is that majority of S/X owners opted for smaller 75kW hour battery, so higher proportion of their charging stops will be into 80% - 90% territory (personally I value my time ... but even so, with free supercharging, I don't bother to rush back to the car, but I certainly don't dwell "because it is free", my total charging bill for 30K miles a year is < £800, Supercharging is 10% of that, if I doubled my Supercharging that would save me a paltry £80 a year ... and I'd be sat waiting at Superchargers for an extra 8 hours a year ...)
Whereas I was quite surprised when people were talking here about what Model-3 they had ordered that a high proportion seemed to be LR (again no data to back that up, but there is a Google DOC / thread here with Model-3 order summary ...)
I'm glad I switched to LR Raven Model-S when I did, given the increase in Tesla numbers on the road. My Supercharging has dropped from 2-3 days a month (given that real-world Motorway 75MPH range has gone from 240 miles to a 300-and-some) to just once in the two months I've had the car - and the 20% increase in efficiency is a pro rata saving on my annual charging bill too ... all the man-maths justification I could possibly need