Tesla laid out their supercharger control pretty explicitly in the March 1st investor day presentation.
No, third party adapters will never work with their system. No, adapter cables are never going to work with their system. The roll out of the magic dock is meticulously planned to do exactly what they wanted to do, and not anything they don't want it to do. In the presentation they laid out not only how strictly supercharger access control and routing is presently, but ways it is going to be even more controlled in the future (i.e. Tesla vehicles automatically reserving supercharger slots they are in route to).
With Tesla, software is king. Without the software overlay on specific stands (the magic docks), no third party is going to be allowed to tap into their network.
Tesla is not "missing out" on anything, quite the opposite. This technology has been ready to go for a while, but was not rolled out until Tesla got the concessions it felt it needed from the Biden administration on funding. Now, going forward, it is Tesla's intent to build out infrastructure for "all the rest", while rapidly increasing the "Tesla only" sites to make sure that their customers will not be impacted by the magic dock users. Keep in mind, it costs Tesla 20 to 30% of what it costs everybody else to put in a DCFC site. They could be hard to compete with going forward when it comes to installing these sites. Financially, I can't conceive of a way E.A. or anybody else is going to compete with them. Tesla is positioning itself to be able to wreck the competition with just the turn of a dial (price). Elon had an enormous grin on his face when he spoke of proving that hypothesis with the recent dial twists on model Y pricing.
Having just sold their 4 millionth vehicle, Tesla is now the 800lb gorilla in the room, and they just announced their future domination plans: 20 million vehicles a year.
A whole lot of really good information was put out in the presentation, some of it telegraphing major shifts for the automotive industry when their competitors were just starting to maybe catch up to their tail lights. Switching all low voltage systems to 48 volt lithium may not sound like a lot, but for the engineers and designers in the room, you understand what an earth shaking leap forward this is in the automotive industry.
And that was just one of about 100 really cutting edge things that were announced during that forum. Tesla is eliminating nose-to-tail wiring at a time when others, Ford included, are trying to figure out just how to wire an EV.
Every auto maker in the world is trying to get to where Tesla was. Then Tesla goes and moves the pins.
Happily, those plans now include charging infrastructure for all EVs.