I kind of do stuff like that... but only in my head.
I wouldn't say that I use the results to help me decide what I might chase next, though. Much like your idea to list the "decade made" and perhaps address those holes, I suppose I did look at what "holes" I had and generated ideas of how to address them.
But I realized somewhere along the line that there's little reward for attempting to "complete" some kind of collection...especially when it led me to buying or chasing some guns that I simply did -NOT- have any desire to own.
So, are you simply showing off the neat pie charts & bar graphs? Or are you also soliciting opinions, ideas and suggestions?
It seems like the most obvious thing to me in the four visuals is that caliber seems to be a curiosity. If it's simply a report as to what's in the cache, it makes sense. But I can't help to see what is listed, and what is missing. Or to put the argument another way... I see that .25 Auto & .380 Auto are listed, and it makes me wonder how .32 Long, .40 S&W, .41 Magnum or .45 Colt don't make the cut.