It's true that nothing changed. But for decades the state has ignored the treaty. This ruling* says that no, the treaty stands and the terms are enforceable.
I'm betting there have been other cases, in Oklahoma or elsewhere, that the argument boiled down to, "Yes there's a treaty, but the state has ignored it for so long that it's not fair to hold this private business to its terms." For instance building on Indian land.
If I were an attorney working for the tribes, I'd look for those cases that were decided in federal courts and file an appeal to the USSC.
* My phone autocorrected that to "trolling", which seems oddly appropriate.