Tesla lied (sorry..."embellished") about opening up the supercharger, the same way they "embellished" practically every other claim they ever made. "Offering" for other manufacturers to use their proprietary standard is not "equal terms". In the real world, nobody would, or even legally could, actually use supercharger technology in their car designs or in any charger designs until it was formally standardized by SAE as NACS in 2022. Tesla finally did that when they realized they would have to do it in order to get government money for charger deployment. And then once it was "actually opened", everyone adopted it.
Furthermore most superchargers themselves are a "shoddy product". Most of them in the field are the obsolete V2 superchargers that only do 120kW, and even the newest V3 supercharger is only 250kW and still can't charge modern 800V cars properly. V4 super charger which is up to modern standards is supposedly "just around the corner" in Tesla speak.
Tesla deserves credit for having a head start but they are legitimately 5 years behind at this point. Their product line hasn't even changed in years, their EV architecture is old, they let Ford stomp them to the enormous pickup truck market with the Lightning, the Cybertruck is a bad joke and there isn't even an announced successor, they let VW stomp them to the minivan market with the ID.Buzz. The supercharger network was the one killer feature Tesla had but with other cars adopting NACS that's not even an exclusive anymore.