So here is a question in the opposite direction then. It seems like there are a lot of people saying the shorter the better when it comes to an RDS on a pistol. If that's the case then shouldn't a G26 w/ RMR be ideal? I own a G26 and 27 without optics. All my optics are on my 19s. With this discussion I was just curious about the other side of the coin. I have no experience with at RMR on a baby Glock and in all honestly I rarely see them out there. I've tossed around the idea of throwing an RMR on one of my baby Glocks but I don't see it being worth the juice in the long run, maybe I'm wrong.
I think the RMR may have more upside on a smaller gun (i think there is upside across the board....just proportionally more on the subcompact). However, most people also look for more bang for the buck, no? Thinking of it that way, how many 26s and 27s do you see even in concealed carry classes? I took Pannone's Covert Carry class and recall only one subcompact. 19s and 17s dominated, even though I bet a lot of those people carry a smaller gun every day.
My point is that if a 19 is the gun you tend to train with (and they offer a nice compromise of full grip on the draw with accuracy, sight radius, etc), and you only have the $ for ONE RMR, then you'll probably put it on the 19 so then you'll get the most use out of it.
It may also be that some people still think of the RMR as more of a competition rather than a combat thing, so never considered putting it on a subcompact.
Finally, the 19 is wildly more popular than the 26 (a lot of people don't like the dangling pinky), so it just makes sense mathematics-wise that you would see more RMRs on 19s.
Indeed, many people say that they can conceal a 19 as easily as a 26 (not me), so they may as well have more rounds and a longer barrel.
I hope some of that makes sense.