It hasn't been reversed by the next rung in the ladder (not sure what's above "appellate")? I would assume something like this would be fast-tracked through the courts more than other issues. We're talking about fundamental government workings, not another abortion bill. It's been five months.

The ruling finding that the tariffs exceeded Trump's authority was only issued on May 28th. The permanent stay wasn't issued until June 10th (a temporary one was issued immediately). It's been only a month, really.

Although we're talking about fundamental workings, whether it's appropriate to stay matters pending appeal also depends a great deal on what the impact is on the parties, and how permanent it is. Generally speaking, courts are far less likely to use their equitable power (the power to issue injunctions) if the matter under dispute is money. If the federal government collects tariffs, and the appellate court agrees that the government shouldn't have collected those tariffs, it's relatively straightforward to reverse the impact on the parties and just have the federal government refund the money. For obvious reasons, you can't really do that with issues like abortion access, where delaying the effectiveness of the decision results in outcomes that cannot be reversed.