The CCS chargers in my area with the exception of one all have some sort of business implication tied to them. We have plenty of Nissan dealers that have CHAdeMO/CCS units to help them sell new LEAFs. There's are free, though I've noticed they don't care about the condition of the equipment. We also have the EVGo stations (which gouge you on price!). The government has a couple of miscellaneous charging programs, but all of them are more focused on workplace charging. One of the programs did create a chain of Chargepoint DC chargers up and down a major freeway, but the gas chain that operates them gets to take home a profit, assuming the repair costs aren't too high. The exception was a city government that used an excess in the budget to install a DC unit, this is also the same city that also has electric buses, so my guess is they eventually hope to use it to charge up the cities EVs. This one is free, unless you happen to pay taxes in that city.
Electrify America promises to make it possible for me to do a battery only drive to a destination I go about 2-3 times a year, but for now REx worked great! We drove by the sites listed in PlugShare and the Electrify America website, and didn't find any hint of construction yet, so we'll see how it pans out. I also hope the rates are reasonable, It would be a shame if buying gasoline for my REx was cheaper than charging!
Now, to get back to the original topic. The i3 is an aging vehicle, but it has been refreshed now. You can get an i3S with a battery that's twice the capacity of the original i3. I think it's reasonable to see it last until 2020/2021, especially since we're already in the 2019 MY. i3 sales are still fairly strong in Europe, and since it's already USA DOT/NHTSA certified, unless import duties get super crazy high, I don't see any reason why they would phase it out here. Using the empty REx space for more batteries seems like a little bit of a stretch, but BMW could very well put something there. I like the fact that BMW has been committed to increasing the battery capacity of the years. Hopefully somewhere along the line I will be able to buy a refurb (or even new) battery cell pack for my i3, giving it longer range. Much of the i3s technology has been slowly integrated into other BMW models. I think part of the i3's interesting design and shape has something to do with the high cost of CFRP. It's likely that a next gen BMW EV will not have a pure CFRP passenger compartment, probably something more akin to the new 7-series' "Carbon core". I'd like to be proven wrong on that, and that BMW is cooking up a worthy successor to the i3 (on a dedicated all electric platform), but it seems like their current direction ATM is to have more G-series chassis, and using the CLAR architecture to electrify existing ICE cars. It seems like a lot of automakers have gone in to "wait and see" mode, especially with the low gas prices here in the USA, and consumer demand for SUVs and other large-ish vehicles. 2020 will be here before we know it, and we will just have to see what happens then.