Back to the OP's question, my friend owns a gun store in town and I spend alot of time in there
. I've seen it time and again....Glock's fly out the door.
Glock is a recognized brand to those that don't have much experience with firearms. They are underwhelming with unnecessary buttons and gadgets. No decockers, no grip safeties, no manual safeties. They are priced right. While a newbie off the street has probably heard of Colt, show them the price tag and they feint.
Its always frustrating, I always tell him that he should be showing them an 870 or some other typ of pump 12/20ga for home defense requirements, which is
usually , not always, why a weapon is wanted by a first time buyer. Like someone said before they are typically going to load it and set in the closet anyways. But I understand pushing a $500 glock vs. a $300 shotgun is definitely a revenue booster.
Another large selling point to complete newbies for Glock, CAPACITY. Most people that have only shot a pistol once or twice quickly realize that its much harder to hit what you are aiming at than they thought. "Give me the one that holds 15-20 rounds please". Also, many new people have a fear of dealing with a cocked hammer...just scary looking to them (in reality its probably safer than the safety system on a glock for a newb.) but its the perception of a "locked and cocked" pistol that could go off if you breathe on it.
Ease of dissasembly... Put a 1911 in a "virgin's hands" and tell them to take it apart and wipe it down with oil....good luck.
Also in today's "high tech" world, revlover's just don't have the cool factor, although that should be their second choice behind a shotgun for ease of use. Remember above statement of capacity, most of these people were at the range and know that 5-6 shots just isn't going to cut it when they only put 50% on paper. Remember we are talking about the newb to handguns. Everything is high tech so Polymer and Rust proof sleek/clean looks are in. Also why sell a $300-$400 revolver when he can get more revenue off the $500 Glock.