I think they confirmed on the earnings call they will open up the charging network in the US. I think the timeline is unclear because:
-unlike in Europe, where it would just be changing some lines of code, in theory, to make all superchargers accessible to all EVs, in the US there would need to be physical changes to superchargers due to the different connectors. I think they have already said that an adapter approach is not desirable or not possible….not sure if this is due to safety, performance, convenience etc.
-they want to make sure they have the capacity for future volumes of both Tesla and non-Tesla cars. This seems to be an issue because according to them, although they are growing the # of superchargers at 33% per year, which sounds like a lot, they are increasing car production 50% per year (last year was more like 80% or 90%).
Seems like they need to build way more stations than they are. My guess is that any “opening up” would be incremental. Perhaps new stations beginning a certain date would be dual cable and then existing stations would be converted on a case-by-case basis based on local usage stats.