It's popularity has reduced by alot in Japan.

The console entries of the 80's/90's all sold over 1 million, all of the console entries since the turn of the century have sold under 1 million

It will have an impact but I dont think it will be that big, specially with the consoles which is why is why I think people say that

Just checked and Chartz numbers for MGS in Japan are undertracked, you can check my signature for something more up to date (although maybe it is because chartz uses MC & I use famitsu)

Still, you have to take into account that Zelda started in the gaming boom of the Famicom a time in which pretty much everything Nintendo put out sold 1m, Metal Gear wouldn't hit big until the PlayStation, if we to compare Zelda vs MGS since then then MGS win, the last Zelda title to outsell a MGS was Ocarina of Time, both MGS2 & 3 greatly outsold Wind Waker, MGS4 sold more than Twilight Princess and Skyward Sword combined.

This is home consoles of course where both series are stronger, in the handheld part makes it more even for them, but as far as consoles go, MGS is bigger.

Actually I think VGC uses the average of MC & Famitsu.

Isn't MC generally seen as more accurate? Regardless, I checked the sales via your source and, while they are slightly larger, they're still not bigger than most Zelda games. I'd say they're on the same level, in terms of average.

I'm not sure how that's relevant though. The Playstation sold about the same as the Famicom, and Metal Gear was insanely popular then too, just as Zelda was. Besides, the series has seen a downturn there as well. MGS4 sold less than its predecessors and Ground Zeroes wasn't popular at all. Zelda is definitely bigger on handhelds, though. 

Like I said, it's about on par. They're both in the medium tier, I believe. Was only using it as a comparison though in the OP. Wasn't trying to make it seem as if MGS isn't popular in Japan, just that the Zelda series is on the same level.

It's not as big in Japan, since it is more popular in the West.

They are but they're data doesn't go as far back as Famitsu :P

There's also stuff like the rating of the games to consider, Zelda is something for a more broad audience while MGS is decidedly more adult (not that it matters a lot)

And while GZ wasn't super popular, it was essentially a demo (an awesome one!) yet it still managed to greatly outsell WWHD, so there's that too.

I'm derailing your thread here, so if you want to compare MGS & Zelda it'll be for another time.

Yeah, I'd say of all the Ninten franchises, Zelda is talked about less in Japan, but I have met some Zelda fans. However, Mario is the big title, and then pokemon somewhat.

Better not look up the Japan sale data of Metroid, you're gonna cry.

I figure it is very low... Japanese people don't talk about Metroid at all, cept one kid I met who likes retro games and said Super Metorid was one of his favorites.

（´・ω・｀）