Might be the reason. Might not. Sequels of games like FF or Pokemon (Black and White 2) never sell that well regardless of the quality of the games. Grand Theft Auto 4 was the best reviewed game, sold extremely well and yet the expansions didn't sell as well as Rockstar expected, despite being good. I think it'd be unrealistc to expect a Mario Galaxy 1-2 (instead of Mario Galaxy 2) to sell as well as the first one (though Mario Galaxy 2 also sold considerably less than 1, despite the larger install base and reviewers saying that it was better than the first and what sequels should be). The title alone makes people not want to give it a chance. 

Of course that was probably not the case with FF13-2 and 3, but I'm sure it played a role.

 Smash 64 stages also had annoying things! Remember the tornadoes from Hyrule Castle or the Pokemon from Saffron City?

Ico did some things well, and differently, and pushed some new boundaries. But some of it wasn't as compelling as it could be at its best, and as a cinematic platformer the appeal for enjoyment is niche. Lots of the experience lies in noticing the details or appreciating the ending and not majority of people will be compelled enough by the kind of monotonous gameplay to finish it.

SotC is simply more compelling and overall a better game. Of course it still has rough edges where it tried to push technical boundaries or do things differently from other games, but I think its design is pretty affecting and it carries over a lot of Fumito Ueda's vision from Ico into a probably superior experience. More engaging.

I think both games benefit in the critical eye from being seen as Ueda's personal projects as an auteur.

Diversification is all that is. There are wacky fun stages and their are many many stages that do not make you deal with such environmental hazards. And Melee just looks and controls better in my opinion, with more options and characters available. I don't know how you see it as a downgrade from SSB64 at all... but if that is your opinion then yes I guess you would find Melee overrated.

Well, it didn't light up any charts or anything. Sold a little over a million units on the dominator that was the PS2, over 250 titles on the system sold better. I don't know what the quota for commercially overlooked is. Under a million?

That's not too bad at all, PS2 had what, 2000 or so games? That means SotC was in the top 10-15%.

Well, Earthbound is pretty different from a lot of JRPGs (and obviously many western ones), so someone who prefers it may not even be interested in over half of those other hundreds of RPG releases over the years. I mean when it comes down to it no one can play every game and tell you the best, but we can all appreciate a great game.

Anyways, I was just going to say I recommend playing the translation of Mother 3 if you did like Earthbound. Don't want to build it up but I think I like it better. Though I did also play it before Earthbound.

Thinking of it that way yes it is up there in the higher percentages. I do have many favorite games that sold far worse! :(

If I remember rightly, MOH was on a downward trend in terms of critics and reviews by the time the original COD came out. A lot of the original MOH team left EA to work on COD (oh the irony!) and I think he hardcore shooter fans knew this and jumped ship. Sales for MOH were still good, but the franchise dropped in popularity with each iteration whilst COD just kept getting stronger from the original's release.

The ship in Fox stage was worse. It had a killer instinct. The barrels in DK stage were... tricky. But I loved the Pokemons in Saffron City. You could beat the hell out of them. Charmander and Chansey could be sent flying if you land a strong hit. Of course, it was better if your enemy release a Pokeball and a Chansey came out, then you could just beat her and she wouldn't go away as long as you keep punching, throwing bombs, attacking with other Pokemons and stuff.