That is an interesting idea, finding the average library size of system owners would be great. My retail experience tells me that the average mass market consumer owns less than 10 games at any one time. Actually, most of them buy a system for one game and then buy nothing until something comes along just like it (usually the sequel). They buy and rent other games, but not to keep them or play them very much.

So, I would predict in this hypothetical study that the more popular the console is the smaller the average owner's library. More owners with less games will drive the average down faster than anything else.