They do care. They also care about partial results. As of last week, we thought we knew the best possible algorithm. We now know that there's a galactic algorithm that's an asymptotic improvement. The question then becomes "Is there a non-galactic algoritm that does the same, or is any such algorithm necessarily galactic?"

The problem is that proving an algorithm is necessarily galactic is incredibly hard. If you knew how to do this, you would become one of the most celebrated complexity theorists of the age. Stanford would be calling.