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This is very true. 

Your response somewhat helped  . I suppose there are morale rules at play here (I'm using AD&D 2e), but...there may be times when a character is shooting the proverbial "fish in a barrel" and I was simply curious as to how you'd handle XP awards in those scenarios.

This premise goes with the assumption that Combat = Experience. A lot of modern games have moved away from this idea, including my own work. However, if we are going on D&D, or D&D like games, there is an alternative here which is Milestone leveling. Here, characters level based on narrative beats, which removes the need to determine the significance of an encounter. That said, my response might feel like a dodge to the question. 
 
Let's look at the scenario provided: 

An unintelligent monster is attacking in an urban environment. An archer is poised in a secure position, mitigating the threat to them due to the creatures inability to reach them.  
 
It's not that this encounter doesn't pose a challenge to the character, it is that they have offset the risk. If the player realized that moving to a rooftop negated the monster completely, I wouldn't want to penalize the PC for creative thinking and / or planning. 
 
As the GM, not knowing the creatures stat block, I might have it attack the building the archer is on top of, like a bear trying to knock something out of a tree, but with the possibility of bringing the structure down. Suffer ye the damage of falling and the joys of being covered in rubble before becoming a snack. Granted, the archer might move to another location, but you can repeat this and it makes the encounter a bit ore engaging. This also brings me to the second tactic. 
 
Unless compelled, if it didn't look like it could get to the archer, I'd have the monster leave. Go look for easier meals, no the archer can stay safe opting not to engage, or give chase. In either scenario I would probably have the monster cause collateral damage, catch someone outside, or other harm. If the player choses not to engage then I might deny them Experience for the encounter, and make it clear that they could have prevented others from being harmed. If they are a paladin, this gets really ugly as they may have broken an oath. 
 
Does that help?  

Because, you're not going to get any better. Taken was fun, not amazing, but it's the best I've seen from that revenge genre. (Sorry, Kill Bill)

These days, I think of fantasy over science-fiction (if only because fantasy is more divorced from the sad realizations of our own existence). When all one has is dreams, it hardly hurts to dream big...
 
You do raise some fair points, however. Space colonization - at this point in our evolution - is incredibly complicated, glacial and almost self-defeating in some ways; we require miraculous advancements (e.g., faster-than-light travel that sidesteps relativistic issues, artificial gravity that isn't spin-gravity, fully protective radiation shielding, truly long-lasting plus safe stasis chambers, energy generation at least as powerful as reliable matter-antimatter reactors, et cetera) to make the endeavor worthwhile. The near-certainty that space exploitation is going to be guided by corporations is disheartening. Now, if you'll excuse me, I'll go back to my former bleak thoughts.

Here I thought you meant bailing on the site. With the added context, my thought is that we have a lot of house keeping to do before we can start looking for a new home. There have been a number of exo-planets discovered that could potentially house human life. However, barring the need for faster means of travel, there are still so many issues we should resolve here first. 
 
When Elon Musk proposed that poorer people could effectively pay their way, much like indentured servants, in his vision for terraforming Mars, that really sent shivers down my spine. As once you are there, there really is no way out of the arrangement, and your boss controls the food you get to eat and the air you can breathe. Total Recall was not meant to be a guide. That's just on the idea of unchecked capitalism and how it looks more and more like feudalism as we remove what limited controls that are in place. 
 
Then you get into societal issues, all the given "isms" of our world. Who would get to go to said haven? In Burning Chrome, there was a short story about a space station in a degrading orbit. The crew had all been evacuated, except for one person who had such bone deterioration from living in space he could not survive on earth. The story ends with a group of people using modified hot air balloons to  reach the upper atmosphere and correct the orbit before the station breaks up. Their goal to form a sustainable colony off world. There's something really innocent and fun in this concept, as they succeed and the remaining crewman becomes a mentor to the new inhabitants. However, I can't imagine this ever happening. Even if we take the events at face value, once this abandoned station is fixed, I can only see the original owners returning to collect. Although, I do like the idea of upcycling at that level.