Interesting stats. Thanks!
I have more. I calculated download numbers for like 94 games on VC and looked at more than a hundred more that sadly didn't have any data.
Not surpisingly, the most downloaded one was SMB with ~245560.
But that really just backs up my point that whether it was ported or not didn't really matter much in the long run. From the stats you gave, FFIII was still the best-selling title on VC (by a long shot), even after it had just received a substantial remake very recently. The game sold well because people like the game - not because it hadn't been re-released before. As I posited before, if the game had received a GameBoy Color or WonderSwan port in 1999 - do you really think that would have affected the DS sales all that much in 2006?
There were only 1,4 million copies to begin with, that circulated on the used market until only retro shops like Super Tomato had FC games. When I hunted for the FC FFs on the net in the late 90ies there were very few sellers and when I found one, the copies were quite expensive. I had no trouble finding FFV though for a good price, which circulated 2,5 million copies and on a console that was still in shops.
In 2002 in Kyoto I had no problem finding all the SFC FFs for 1000 yen, with boxes. I one time even saw the FFI+II cart for FC, but not the original releases for any FC FF.
Of course in Osaka or Tokyo there were shops which surely had it, but it wasn't readily available everywhere. As opposed to FFV onwards (2,5 million used copies plus PS and GBA ports) but also to FFIV, which only had the same 1,4 million copies as III but on a console still in most stores, and the same two ports as the other SFC ones.
People liking FFIII so much also contradicts polls and surveys, were usually FFVII, X and IV are the most popular. III definitely isn't more liked than IV.
There's really no other explanation for the bigger DS III vs. IV numbers other than saturation. IV had higher production values, with voice acting. The VC release doing so big after the DS one also would contradict people having disliked the remake and therefore avoiding the follow up.
....it's Dr. Kawashima..never played Brain Age/Training?
Actually it's Professor Kawashima (Kawashima-kyouju), as opposed to Doctor (hakase). No idea why Nintendo made him a Doctor in the West.