Hmmmm, yes and no. There is everything from hours to mere minutes to get ambo from its parked spot on scene to the ER. And there are systems which reflect that as well, from the do as little as possible/load and go cause we are so close to the systems which say proximity to the ER should not be a factor in your clinician skills/assessment/care and treatment.
And within those systems there are those who abuse it or take advantage of it, depending on which side of the bed they woke that day.
I am unsure what exactly your point was or which direction you want to go with your post, but there are way more dynamics to how long a scene or transport should take within all rural or urban environments than simply assessing the way the crow flies.
Where I live part time of the year (rural) if the roads are dry, weather is fair, and traffic is light....I can be at the ER within 30-40 minutes. Other times of the year the trip could take 1-2 hours due to inclement weather, snow, bad roads, etc.
I also live where a 4 mile section of road easily takes 25 minutes to drive due to pot holes, switchbacks, hills, and many other interesting obstacles most urbanites would never think about. On the flip side, I typically do not have 3 level walk ups on narrow dark stairwells to navigate along with every busy body either inquiring about what is going on or trying "to help".
Again, just far too many dynamics which we could probably write about for days on end, however I think the more important time factors are response to scene and then scene time. Short of a significant trauma, Stroke Alert or Cardiac Alert....I can handle everything else and am quite happy to take all the time needed to do so and could care less about the "transport" time.
Edit: I can handle the above mentioned things...just not in the way their condition warrants. Did not want it to sound like I was lost on those, lol. Was trying to stress the time factor, but even knowing time is essential, I will not jeopardize myself or my partner and take short cuts or unnecessary risks. I will do all I can for the patient within reason and what is, shall be.