I know every landing I make, I will try to turn off prior to the end of the runway. In general, the quicker you're off the runway, the smoother the flow of traffic is. I can tell you, if you land at LAX
and plan on taking it to the end, you will spend some time in the "penalty box". I have seen it happen!
As far as watching the traffic at CMH
, unless you had some type of radio to monitor the tower freq, you don't know the whole story.
Plus, just because it's a late night flight, that crew might have another 2-3 days flying to look forward to. They could be just going to another layover.
Finally, remember, we get paid from block out to block in, scheduled or actual which ever is greater.