The Court was stuck, however, by the fact that this loophole doesn't involve an obvious circumvention of the "limited terms" clause at any specific step. At best, the Court might find a "clear pattern" rationale if Congress extends and re-extends copyright terms a few more times. If so, the issue might be resolved sometime in the latter half of the twenty-first century.
Yes, and at that point it might be appropriate for the Court to intervene. Absent that rationale, though, they would just be second-guessing the legislature as to what the "correct" term of a copyright should be. I frankly applaud them for not doing that. I wish more judges would be that reticent to substitute their own judgements for that of elected legislatures. I could never figure out how the Florida Supreme Court came to the conclusion that they were free to jack around with the deadlines specified in Florida election law. When they did that, they essentially turned themselves into a House of Lords with the power to amend legislation as they saw fit. That they were overruled by the U.S. Supreme Court did not surprise me a bit.
I think the real gripe here is that people are frustrated by the fact that a special-interest lobby bought itself some lucrative legislation. That's a problem, but the courts are not the right place to try to fix that.