That article you linked to isn't saying what you think it is.
I specifically would like to see the superchargers opened up to all vehicles as well, but the details of the article state that they are only doing this in very select locations/markets, and primarily focused on those which were built with government subsidies.
We are not likely to see the vast majority of the Tesla charger locations opened up to other brands for a while, and that may come via regulation.
1. This is happening in Europe is, which is the place where they are already losing market share
2. If they agree to open their network in some markets, the rest of the world will soon demand the same.
Also: Tesla is planning to open up their chargers network to other cars [1]. So either they have a plan to ditch car manufacturing and focus on chargers network (and battery production), or they are digging their own grave.
[1] https://electrek.co/2021/06/24/tesla-confirms-plan-open-supe...