The Supreme Court said in Loper Bright that previous cases decided under Chevron are still good law. But this lawsuit challenged a brand new FCC order that had not been previously litigated.
The court is saying, if we had litigated this (and most likely upheld it, because Chevron) then it could stand now, even after Loper Bright. But if we never looked at it before, then we get to use the new rule.
That doesn't make a lot of sense.
Like, the counterfactual is they litigated and upheld the order, so it's safe. But because it was never challenged before, it can be challenged now. Only orders that were challenged are safe.
It would make more sense to do it the way I thought: everything, even if it wasn't challenged, that would have relied on Chevron still can rely on Chevron. That gives "the benefit of the doubt" to the agency that passed the regulation in the Chevron era.
In the new scheme, the regulators have to comb through all their orders going back decades, figure out which ones were never litigated, and figure out how to defend it without Chevron.
It would be weird if, for example, the Supreme Court said that gay marriage is constitutionally protected but all the existing laws banning it could stand because they were enacted earlier.
I'm fairly certain the regulated entities will take this upon themselves and will create the lawsuits that provide the opportunity for the administrative agency to defend their position.
If they're that concerned, then they should get with Congress, and get a new law passed. This is precisely what Chevron was meant to create. Administrative agencies simply cannot unilaterally create and enforce law anymore.
OTOH, I think/hope the courts are sending a message to congress that they need to work out more details in the laws.