To me this has always been the rule:
Pistol: point blank to 15-20yards
Shotgun: Point blank to 50-75yards
Rifle: Point blank to 200-300yards
Can they be made to shoot further with training and practice:
Of course.
Could I do much better minute of man with each tool at those ranges if scared, fatigued, and/or full of adrenaline:
Honestly, No, if I'm being realistic
You can see that in my perception there is quite a bit of overlap as to what each tool can do. But, to me, each one excels at a solving a different problem.
For example, why would you use a long, long screwdriver, meant to get into tight/cramped spaces, to take the battery cover off a kids toy. If long screwdrivers are all you have around due to the nature of most of your work, then you are definitely justified in using what you have to get the job done. Similarly, why would one use a long firearm, with a slowish reload time and limited capacity, if given the choice.
Most on this board tend to have guns that suit a particular task, just like most of us have a toolset that allows us to work on a variety of "Mr./Mrs. Fixit" problems. We tend to have long, medium and short screwdrivers that allow us to do a variety of jobs, just like we own at least one example of each type of gun. There are others, though, who simply prefer a particular style of firearm, be it pistols, shotguns or rifles. That person would likely be, without fail, VERY good at using that firearm type to its fullest potential due to intimate familiarity with it's charactoristics.
So, as was said above, I also subscribe to the logic that it's the operator/user of the tool, not the tool itself that makes the difference.
Long post, to be sure. I guess I felt like giving you my LONG answer. Cheers.