Just curious where the "one last big system" sentiment comes from?
Climatology. It's unusual for the jet stream (and associated troughs) to remain this far south at this point of the year. Thus people assume that the jet will soon be moving into Canada OR a death ridge will be setting up. I've seen this death ridge show up in some long-range FIM forecasts several weeks ago, but the forecasts never verified, probably because this year is so unusual, it's trending away from climatology. Given how late everything has been this year, it's probably not out of the question to see troughs continue for another few weeks before we see a true abatement of large-scale storm systems anywhere but near the Canadian border.