Quote History I don't understand that meme.
On AR's today, outside of the top rail, how much of the rest of the rails are ever used? Maybe bipod or grip (which can be mounted either with a section of pic or direct mlok)? Every now and then a light or something at 3 or 6 at the end of the rail?
Outside of the top rail, 87% of the rest of the quad rails are not used.
I also think there is as time/era factor. Do you have something with carbine gas and an A2, plus a carry handle where you basically have no room for anything and you are hanging shit off the sides?
Upper looks like this and you want a light and a laser....and maybe an optic on top of the carry handle, yeah, you might need a quad rail.
However, with more guns running mid-gas, followed by low-profile gas blocks, and folding buis (or no back-up sites because optics have gotten better), you now have much longer rails that offer more hand space, and laser/lights can go and the far end of the rail.
You can see how things have evolved. (Shocked the bottom image has the light at 4:30 instead of 1:30)