If it was me just out of curiousity I would have tried to stay near the planet for a little longer just to see how far they would advance. What happens to a species as they continue to evolve? Do they develop better and better technology, and to what end, do they destroy themselves?
I don't think they would take the risk. In all the centuries (planet surface time) ahead of them, all it would take is just a single aggressive government that decides to take them down after all. They were already almost destroyed as it was, Voyager wouldn't stand a chance against weapons centuries more sophisticated and being at that huge tactical disadvantage of living in much slower time. Also, they are uninvited guests in that people's territory.