I love not having to pay for my $10 worth of electricity as much as anyone else, but I fully realize that it is only possible due to the fact that there are so few of us. That will change, and as it does, the free-for-all model will need to change as well.
Mike
If you want ppu, then by all means, use a Chademo. Your cost of entry will be ~$500 for the adapter (delivered, with tax) plus however much you wish to pay for the sessions.
There is no free for all model. Going forward, you will have the option to pay one time or not at all. Ppu will do nothing to reduce congestion as there are already numerous one-time payers. Further, there is no problem today at 97% of SCs, nor will there be a chronic problem at those SCs. Of course there will be ebbs and flows during peak holiday periods, just as there are at the neighborhood Costco.
The biggest problem in areas of density is and will be ICEing by our own (and of course by ICEs, although during a 12,000 mile road trip this past month I saw that only twice). Saw it again yesterday by a known livery driver who seems to think it's ok to take his midday 90-minute break when he needs only an hour of charging at most. Bad practice today, and bad practice tomorrow - real quick way to turn an 8-stall SC into a 1-stall SC no better than the neighborhood Chademo.
Insofar as big picture resources and global health go, Canuck is absolutely correct. In time (not exactly soon, but "soon"), solar will supplant combustibles. When I was at the Powerwall event in Hawthorne, and you may remember the graphic, it was pretty striking to see that little speck in Kansas with Elon noting if said speck was covered in solar panels, it would power the entire country. Driving south into Los Angeles through the desert, you quite literally can't see the end of the solar farms that are already built - they are huuuuuuuuuuge, and even so are barely the beginning of what's to come. A little closer to home, at some point, SCs will be at the least solar-assisted at many (obviously not all) locations - Quartzsite, Arizona, for example. Twin Falls, Idaho... anywhere with cheap real estate, really.
As for density (e.g., Vancouver or Los Angeles County), you either trust in Tesla to manage density demand or you don't. So far, they have. Most owners don't use SCs, and a large percentage of Model 3s won't opt for SCability in the first place. And so it goes. I'm not saying they won't experiment with ppu at some point well down the road (at about 1,000,000 vehicles as Messrs Straubel et alia noted). I just don't think it will happen first in North America, nor for years yet.