You are mixing things up. You are talking about MagicDoc, which are Superchargers that have both NACS AND CCS adapters built in... This has nothing to do with the now opened up Supercharging network, other than 100 sites do not require an adapter to be self-provided.
v3 superchargers and up speak "CCS" the required language needed for charging non-Teslas. Any v3 and up Supercharger will work with Rivian, Ford, and there have been reports of a couple GM test vehicles. You also have to remember that Teslas didn't always speak CCS. My 2019 TM3 did not speak CCS, my 2021 TMY does. I had my 2019 retrofitted. I'm still willing to bet that majority of all US based Teslas do not speak CCS (considering TMS from 2012 - sometime in the 2020's didn't come from the factory CCS enabled). So, this is a MAJOR undertaking to open the charging network to something that wasn't actually built into the original design.
There are 2 things that are needed for non-MagicDock stations.
1. The vehicle manufacturer needs to develop software that will communicate with Tesla (this allows for contactless payment directly with your card on file with your vehicle's manufacturer).
2. an adapter (until you have a non-tesla with built in NACS) which are provided by Tesla to the vehicle manufacturer. There also are 3rd party adapters (up to you, if you trust it, but you do risk voiding your warranty and getting sued in the event of a fire/problem).
Now, my thoughts. Tesla spent 10+ year developing the Supercharging network, they do the best job of maintaining their chargers, but it costs money and time to replace chargers. They are a private company, they did take Government money to open their network, which I'm not 100% sure, but I believe the MagicDock stations already have met the opening up mandate.
I hear no complaints of Rivian/Ford not changing their vehicles design to have a built in NACS port. If they did, they wouldn't need an adapter, and they wouldn't have to wait for Tesla to produce them... They have had the same year you mentioned, yet, there are no current vehicles they produce for sale with the NACS port built in.
Most of these chargers that are available to non-Tesla vehicles that have partnered with Tesla or are MagicDock which are open to anyone (I believe the 100 sites you talk about are MagicDock)
Tesla SuperCharging Network Map
View attachment 2418935
If you click on the site you will see if they are open or not:
You also should remember that Tesla doesn't only have 1 charger at each site. Tesla does a great job of putting in as many chargers at each site as they can. When you see other CCS L3 charging sites, many of them or 1 or 2 only.