[jeffbee]

As pointed out in other comments this process is entirely by choice of the court. In other cases where they just felt like ruling on something they have put things on their emergency docket and ruled on them immediately. Letting this situation ride for a year was a choice by the court.

[AnthonyMouse]

Not doing something you could have done is frequently less of a choice and more of a lack of bandwidth to simultaneously consider everything which is happening at the same time. The vast majority of cases don't make it onto the emergency docket.

[loeg]

Many reasonable people would argue this was significant / enough of an emergency to justify devoting that bandwidth, even by the standards of the Supreme Court.